MANUAL OF HEAVY ARTILLERY SERVICE, UNITED STATES ARjif^ TIDBALL. 1880. m AUl'HORITY. [BY AUTHORITY.] MANUAL OF HEAVY ARTILLERY SERVICE. PREPARED FOR THE USE OP THE ARMY AND MILITIA OF THE UNITED STATES. BT J. C. TIDBALL, LIEUT.-COL. FIRST ARTILLERY, BVT. BRIG-GENL., U. S. A., COMMANDANT OF THE ARTILLERY SCHOOL, FORTRESS MONROE. THIRD EDITION. WASHINGTON, D. 0. : JAMES J. CIIAPMAX, —AGENT.— 1884. UF/S3 -rr Entered according to Act of Congress, in the year 1880, Dy James J. Chapman. In the Office of the Librarian of Congress, at "Washington, D. O. Press of Thomas McGill & Co., WASHINGTON, D. C. -^PREFAEE.-^ The basis of this work, so far as the Service op the Piece and the Mechanical Manoeuvres are concerned, has been the "Circulars of the U. S. Artillery School," supplemented by the unwritten customs and practices of that institution. In Field Intrenchments, "Mahan's Field Fortifications" was used as a reference, supplemented by the methods intro- duced during the American civil war of 1861-65, and adopted and practiced during the Franco - German and Russo - Turkish wars. In Submarine Mines, the works of Stotherd and of Sleeman have been taken as authority. In other parts of the work, Benton's "Ordnance and Gun- nery," Eoberts' "Hand -Book of Artillery," "Ordnance Notes and Memoranda," "Ordnance Instruction U. S. Navy," "Ord- nance Manual U. S. Army," together with many other author- ities, have been consulted. In the labor of arranging and preparing the plates, and in various other matters, I am indebted to Lieut. C. Chase, 3d artil- lery ; and to Lieut. L. V. Caziarc, 2d artillery, for the admirably- arranged Index. J. O. T. Fort Monroe, Va., June, 1880. (iii) M44/^J/I IV PREFACE. Report of the Staff of the U. S. Artillery School on a system of instruction for heavy - artillery troops^ submitted by Major J. C. Tidball, 2d artillery^ Brevet Brigadier- General, U. S. A. Headquarters U. S. Artillery School, Fort Monroe, Ta., November 17, 1879. The Adjittant-G-eneral of the Army, ■Washington, D. O. Sir : The MSS. for a system of instruction for heavy-artillery troops, pre- eared by Major John O. Tidball, 2d artillery, Brevet Brigadier-G-eneral, ^ S. A., having, in accordance with the instructions of the General of the Army contained in indorsement dated Headquarters of the Army, May 16, 1879, on Major TidbaU's letter of March 29, 1879, been referred to the Staff of the U. S. Artillery School for examination, the Staff respectfully sub- mits the following as its report thereon. The work has evidently been designed to supply a want long felt in the artillery service, and which has been pointed out in G-eneral Orders No. 3 of 1876, Headquarters of the Army, as being a regular and more comprehensive system of instruction or manual for heavy-artUlery troops. Its general divisions are : 1. Preliminary Instruction. 2. Service of the Piece. 3. Mechanical MancBuvres. 4. Care and Preservation of Artillery Material. 5. Transportation of Artillery. 6. Organization and Command of Artillery. 7. Employment of Artillery in Campaign. 8. Employment of ArtUlery against Armored Vessels and in Har> bor Defense. 9. Field Intrenchments. 10. Attack upon Intrenchments. 11. Submarine Mines. To which it is intended to add a short chapter on Artillery Salutes and Ceremonies and Courtesies between land and naval forces, which has al- ready been submitted to the G-eneral, of date October 18, 1879. The Staff has the honor to report upon the various divisions of the work as follows : 1. Preliminary Instruction. This embraces: 1st. Definitions of the various kinds of artillery, and a tabular statement of the U. S. system foi land service; 2d. The formation and marching drill of heavy-artillery troops, — being "battery," "platoon," and "detachment movements," and " subdivision movements," or those common to all three of such tactical sub-units. This section of the MSS. has met with critical trial, (with troops on the drill-ground,) close scrutiny, and lengthy discussion, with a -view to deter- mining what may be best calculated to insure to the service the best means for the performance of duty devolving upon artillery troops. It is found that the proposed marching drill is based upon that laid down in the already-accepted foot drill for field artillery, and that the latter has been modified only so far as the peculiarities of the heavy-artillery service render necessary or desirable; such, for example, as emancipation from the "lock step"; the omission of "section" movements as only essential for field artillery ; the assimilation of the movements of the guides to those of PREFACE. V the infantry, and a discontinuance of the requirement from detachment chiefs to repeat all commands, as tending toward confusion and being entirely unnecessary. The few additional movements are essentially adapted from the infantry tactics, and render the proposed marchinjr drill complete. It is the judgment of the Staff, that while the proposed drill is essential for the service of heavy artillery, and also fully suited for all the duties of artillery troops in garrison or elsewhere in the presence of guns, it is at the same time so closely assimilated to the tactics of infantry in its principles as to render the transition of heavy-artillery troops into infantry formations a thing of quick and easy accomplishment. The same, moreover, may be said in reference to its adaptation for the service of field guns, although its departures from the authorized foot drill for field artillery are but slight, and always in the direction of assimilation with the infantry tactics, which is understood to be the published policy of the General of the Army in such questions. The Staff is therefore of the opinion that the adoption of this section of the MSS. under consideration will in no way impair the efficiency of the artillery regiments in the infantry duties which they may be called upon to perform, while it will, on the other hand, facilitate the duties pertaining to their special arm, because its tendency as a means of discipline and esprit du corps is to strengthen and confirm habits of thought in that direction by continually reminding the men of their weapon as artillerymen. 2. Service of the Piece ; 3. Mechanical Mancetjvres. These sections embrace the drill for all classes of pieces known as heavy artillery, and the MSS. are the result of several years' experience at the Artillery School, of daily study, experiment, and observation. The Staff has carefully examined, revised, and tested this section at the guns, and is of the opinion that it meets the requirements for handling the ordnance now in use. 4. Care and Preservatiox of Artillery Material ; 5. Transporta- tion" OF Artillery. These sections embrace the care and preservation of all classes of guns and their belongings, together with the care of stores and of magazines; also the transportation of artillery under all circum- stances of service, including railroad and water transportation for artillery material and animals. The MSS. are the result of a life-time's extended experience in the U. S. artillery service in peace and war. Much of the matter is derived from actual experience in the war of 1861-65, and has never been published in any book or report. The Staff is confident that it supplies a vacancy in American military literature. 6. Organization and Command of Artillery; 7. Employsient op Artillery in Campaign. These sections embrace all of a subject of great magnitude, which is indicated by their titles, that there seems room for in a book of the kind under consideration. It cannot be doubted that there is to be found in the artillery of modern war the points of support with which to counteract the effect of the open nature of infantry fighting consequent upon the breech-loader, and that it is the stable element of battle of to-day in the hands of a G-eneral, because the dispersed order of the infantry for action renders command of that arm at all times difficult, and quite im- possible as the fighting progresses. There can be no doubt, furthermore, that the object which artillery has to attain must be comprehended from the beginning of its action, and must not be left to chance. It is therefore advantageous, to say the least, that there should be one command ; for the reason that everything becomes simpler and the carrying out of the fight more certain, because more unity of will pervades it. To support this \'ipw, it is not deemed necessary here to expatiate upon the advantages of the employment of nrtillery in large masses, because the object is self-evident and is accepted by most officers of experience and cul- ture as an established fact. These sections of the MSS. are the result of VI PREFACE. the war experiences of the American artillery, and have followed closely the system pursued at the close of the war of 1861-65 in points of organiza- tion and command, although the modified conditions of the battle of to-day have presented a few corresponding modifications in the employment of artil- lery which have been fully treated in addition. Although we have passed through one of the most sanguinary conflicts of modern times, in which the genius of the American soldier was severely tested, and the nature of the "^ terrain'^ entirely difierent from any which is treated of in the text-books heretofore used by our officers in study, and althoiigh we have been at pro- found peace with the world for fourteen years, with ample leisure for such undertakings, it is a singular fact that no American work is extant which is based upon our experiences, giving authoritative instruction in the applica- tion of our arms, beyond what is laid down in the drill-books. Now, the necessity for such works is self-evident ; for although we are not a warlike people, we possess an inherent military spirit which requires direction to be available in the public defense, and such text-books tend to imbue our armies with character and military intelligence when action is required of them. This is especially so in the case of auxiliary troops, such as volunteers and militia. The Staff" is of opinion that these sections of the MSS. constitute a step in the right direction ; and while the subject-matter pertains largely to field artillery, it is not considered as tenable as against its publication in this work, because it is germane to the artillery service in general and impor- tant to be preserved. Moreover, there is no just reason in favor of such a divorce between the light and heavy artillery service, any more than there has been found one in favor of such a separation of the light and heavy infantry of the past. The proposed composition of an artillery force in regard to pieces of long range, or for the development of curved fire in the field, is remembered by the Staff" as identical with our practice in the war of 1861-65, and the princi- ple involved is confirmed and strengthened by the m.ore recent experiences of European nations, notably in the Franco-Grerman and Busso- Turkish wars. The increased zone of effective infantry fire calls imperatively for long- range artillery of great accuracy and quick manipulation, so far as guns are concerned ; while the universal use of field intrenchments, already rendered necessary by a murderous infantry, demands with equal obstinacy the full use and development of curved fire from mortars on the part of artillery, both in the attack and defense. The provision in the MSS. for the nse of such pieces as we now have in service is therefore regarded by the Staff" as an advance toward meeting these new questions as far as possible with economy, while it reserves for future settlement the question of improved artillery material in view of these demands. With these views, the Staff" cannot too strongly recom- mend these sections of the MSS. for favorable consideration and publica- tion. 8. Employment op Artillery against Armored Vessels and in Har- bor Defense. This section embraces as much of this important subject as will admit of a proper limit in size of the book under consideration. It is a subject upon which little or nothing has been written, and the expressed desire of the General of the Army that it should be included, is regarded as sufficient reason for presenting it. 9. EiELD Intrencievients ; 10. Attack on Field Intrenchments, The MSS, embrace in these sections as much of the subject-matter indicated by their titles as is deemed essential. It is necessarily a compilation upon a subject which is older than the service itself, and the Staff" is informed that it is inserted upon the sugges- tion of the General of the Army. Further comment, therefore, seems un- called for. PREFACE. Vll 11, SuBMARi>rE Mixes. This subject is not only important, but highly essential to be understood by artillery troops, upon whom such service will most likely devolve in war ; and while secrecy in the matter of particular inventions may be desirable, such secrecy is easily within the control of the governm.ent. The Staff finds no reason against a publication of so much of the subject of submarine mines as these MSS. embrace. In conclusion, the Staff is of the opinion that, as a whole, Major Tidball's work is full and complete for the present use of the artillery service ; that it is in harmony with the experience of the Army in war as well as with the spirit of its organization and instruction in peace ; and that it is calculated and is probably invaluable,f or the instruction of volunteer and militia artil- lery, upon whom much of the service of heavy artillery will devolve in any war, and whose attention should undoubtedly be directed to such instruc- tion in peace, rather than toward field-artillery drill merely, as is now the custom. In this latter connection the Staff respectfully invites attention to the fact that the maintenance of miilitia field batteries in peace is expensive, and never attended with warrantable success from the very nature of things, and that this branch of artillery can only be kept up in efficiency by the government. With these views, the Staff of the U. S. Artillery School feels warranted in submitting Major Tidball's work for the favorable consideration of proper authority, recommending its immediate publication. It is also respectfully recommended that the work be adopted for the Army and for the Militia. "We have the honor to be, very respectfully, your obedient servants. Headquarters of the Army, Washingtok, D. C, December 10, 1879. Hon. Geo. W. McCrary, Secretary of War. Sir: I have carefully examined the manuscript copy of the proposed Heavy Artillery Tactics prepared by General Tidball, and the reports and papers relating thereto, and find — 1st. That the manuscript of the Tactics (a better designation would be "Manual") consists of twelve parts. ******** As already indicated, it would seem that a modification of the title of the work is desirable, and I would suggest the following, viz. : "A Manual for the Heavy Artillery Service, prepared for the use of the Amiy and Militia of the United States, by Major J. C. Tidball, 2d artillery, Brevet Brigadier-General. U. S. A., 1879." With the title thus modified, the work will consist of parts numbered I, n. III, IV, Y, YIII, IX, X, XI, XII, or ten out oi the twelve parts prepared, and I therefore recommend that it be published accordingly, as modified. The degree of authority to be given it might be based upon that given January 24, 1876, to Roberts' "Hand-Book," or thus: "The Manual for Heavy Artillery Service pi'epared by Major J. O. Tid- ball is hereby apjjroved, and will be adopted as a text-book at the Artillery School at Fort Monroe, and used by the artillery companies (batteries) garrisoning the sea-coast forts of the United States. (Signed) G. W. Mc- Crary, Secretary of War." I have the honor to be, your obedient servant, (Signed) W. T. SHERMAN, General. Approved: (Signed) GEORGE W. McCRARY, Secretary of War, CONTENTS. PAGE. Marching Manoeuvres 5 Definitions 34 Ammunition 41 Implements , 53 Aiming and Motion of Projectiles 56 Carriages and Platforms 65 Service of the Piece. (General Rules.) 79 Service of Siege Gun; Siege Howitzer; 10-inch Gun; 100- pounder Parrott; 15-inch Gun; Flank-casemate How- itzer; 8-inch Rifle (converted); 10-inch Siege Mortar; 8-inch Siege Mortar ; Coehorn Mortar ; 13-inch Mortar ; 10-inch Sea-Coast Mortar ; Gatling Guns 83 Target Practice 183 Telemeters and Pressure Plug 192 Mechanical Manoeuvres, (General Directions.) 199 Mechanical Manoeuvres with Siege Gun ; Siege Howitzer ; Siege Mortars ; 13-inch Mortar 204 Cordage; Blocks and Tackles 231 Machines and Appliances for Moving Heavy Artillery 242 Mount and Dismount the Flank-casemate Howitzer; 15-inch Gun; 10-inch Gun 271 Gun-lift; Shears; Derricks 2*79 Preservation of Artillery Material 293 Inspection of Cannon 301 Magazines and Store-houses 312 Transportation of Artillery 321 Harbor Defenses ; Strength and Composition of Batteries ; Artil- lery against Armor 343 Field Intrenchments 357 Attack and Defense of Positions 403 Sieges; Defiles; Rivers; Demolition 407 Submarine Mines 425 Permanent Fortifications. (Outlines of) 458a Salutes, Ceremonies, and Official Courtesies 459 Appendix 2 4 V «a Index 479 Illustrations Plate 1 to 77 (viii) HEAVY ARTILLERY, U. S. Army, 1879. 1, By the term Artillery^ is understood all fire-arms discharged from carriages, in contradistinction to small arms^ which are dis- charged from the hand. It also denotes the particular troops employed in the service of such fire-arms. i. Artillery is known as Light Artillery and Heavy Artil- lery, Light Artillery is formed into batteries and equipped for field evolutions; Heavy Artillery embraces all artillery not so formed and equipped. 3. In the land service of the United States there are three kinds of pieces of Heavy Artillery^ viz. : tlie GuN, the Howit- zer, and the Mortar. 4. They are distinguished, according to their principal use, as Siege and as Sea-Coast Artillery. 5. Siege Artillery is used in the attack of places, and, as it accompanies armies in their field operations, is mounted upon carriages, which serve for its transportation. It is also employed in the defense of field works. It is then sometimes called Garrison Artillery. 6. Sea-Coast Artillery consists of the heaviest calibres, and is used for the armament of permanent works, chiefly on the sea- coast. Their carriages do not subserve the purpose of transpor- tation. 7. For the service of Heavy Artillery there are four distinct kinds of carriages required, viz. : the Siege, the Casemate, the Barbette, and tlie Mortar. 8. The following are the kinds and calibres of Heavy AHillery belonging to the present system of artillery for the land service of the United States. Note. — The term ''system," as here used, refers to tlie char- acter and arrangements of the material of artillery, as adopted by a nation at any particular epoch. (1) INTRODUCTION. PIECES. BiND. Gun Howitzer. Mortar. Calibke. 20-in. 15-in. " ' 13-in. 12-in 10-in 4.5-in 8-in 5.8-in.— ( n a n k casemate).... 15-in 13-in 10-in 10-in 8-in Bore. Smooth. 5.8-in. (Coehom) Smooth. Rifled. Weight. 116,000 49,000 37,000 52,000 40,681 3,570 2,600 1,476 17,120 3,700 1,900 1,010 164 Designation. Sea-coast. Siege. Sea-coast. Siege. In service^ hut not of the system. G-nn. ••••••••• «< lO-in Smooth . 15,000 Sea-coast. t( tt tt <{ tt tt tt tt Siege. 8-in t( 8-in. (converted) 10-in. 300-pdr.1 8-in. 200-pdr. 1 6.4-in. 100-pdr. f 4.2-in. 30-pdr.. Rifled.. « 16,160 26,000 16,300 9,700 4,200 Parrott... Note. — The 20-inch and 13-inch smooth-bore, and the 10 and 12 inch rifle guns, as likewise the 15-inch mortar, may be regard- ed as experimental pieces, not more than two or three of each kind having been cast. Carriages for them have not 5'^et been determined; consequently instructions for their service must be omitted. The 4.5-inch siege gun, 8-inch siege howitzer, 5.8-inch (flank- casemate) howitzer, the 5.8-inch (Coehorn) mortar,, and the 4.2- inch (Parrott) siege gun are mounted on wooden carriages ; all other pieces on iron carriages. It is intended that the 15-inch smooth-bore and 12-inch rifle guns shall have the same carriage ; the 10-inch smooth-bore and 8-inch rifle the same carriage. The 10-inch smooth-bore and the 200-pounder (Parrott) have the same carriage, and the 8-inch smooth-bore and lOO-pounder INTRODUCTION. 8 * , ) TOO PRELIMINARY INSTRUCTION. 10. The officers and men for Heavy Artillery duties should be thoroughly instructed in the *■" School of the Soldier," LigJit Artillery and Infantry Tactics. The preliminary instructions herein given are only such as are, in addition, necessary for the more general duties of artillerymen. 11. The term piece^ as herein used, applies to cannon, wheth- er gun, howitzer, or mortar. As a matter of convenience, it is also used to designate both cannon and carriage when the can- non is mounted. Detachment, 12J. The men employed in the service of artillery are called artillerymen. The artillerymen for a single piece constitute a gun detach- ment^ and vary in number with the size and kind of piece. 13. The detachment [Fig, 1, Plate I) is- composed of two non-commissioned officers, and from two to ten privates. The senior non-commissioned officer is called chief -of -detachment ; the other, gunner. The privates are called cannoneers. 14. The detachment is formed in double rank, and told off from the right as follows : No. 1 is on the right of the rear rank; Xo. 2 in front of No. 1 ; No. 3 on the left of No. 1 ; No. 4 on the left of No. 2 ; the other numbers follow in the same order, €ven numbers in the front, odd in tlie rear rank. When, by facing about, the front becomes the rear rank, the numbers of the cannoneers do not change. 15. The chief-of -detachment., when in line, is on the right of the front rank of his detachment. When, by facing about, the front becomes the rear rank, he does not change to the other flank, but steps forward into the rear (now become the front) rank. When in column of files, he is as if he had faced with his jn line. When he is the left gnide of the battery or platoon, and by Jacin^ about the front becomes the rear rank, he does not quit his position on tlie flank of his detacliment, but steps forward into the i-ear (now become the front) rank. IT. Wlien, by wheeling: about, the riglit subdivision becomes the left, the g^nnner who was the left i^^uide resumes his place in rear of ins detachment, and the prunner of the detaclnnent which has now become the left places himself on its left flank as guide of the batterj' or platoon. Flaioon. 18. T\\*o or more detachment^! form a platoon, commanded by a lieutenant ; and, if ciiXMimstances will permit, the battery will be divided into as many platoons as there are lieutenante to Ci^mmand them. Battery, 19. The term battery is now applied to what was formerly called a oomi^>jiny. It is also used to designate a number of pieces of ,ariillery in position for service; likewise the place in a work when* they may bt» located ; and it further denoteii cer- tain p<^itions in the manoeuvres with individual pieces. When- ever this term is used, its meaning must be determined from the context. ^O. The battery is assigned to specified pieces in the work, the number dejHMiding on the strength of the K-ittery; the lat- ter is divided into a like number of detachments, and these are assigned to the individual pieces. Although thus assigned to the service of specified pieces, the several detachments should be Instnwjted for the service of any piece in the command. The men of each detachment should be selected for their individual fitness for the \^rticular piece. ^ 1 . The detachments receive permanent numbers, from right to left, tlie first detj^chment being on the right. Platoons are in like manner permanently designated. ^^ During the roanoBUvres, platoons temporarily change tlieir numbers, when, by wheeling, or by facing, the original rigiit btxx>mes the left. ' In column, they are numbered from the head, the leading one bc^ng al\s^ys the ^A^. 9^ The men of cadi detachment fall in\according to lieight^ the tallest men on the right: thus bringing, as a genenal rwle* Ihe ^longest men to the duties requin^ir ir^*atest stn">irtb. PRELIMINARY INSTRUCTION. Posts of officers^ non-commissioned officers^ 8fc. 24. {Figs. 2 and 3, Plate I.) The captain^ in line, is four yards in front of the centre of the battery; in column, on the side of the guide, or on the side towards whicii the subdivisions are dressed, four yards from the flaniv and opposite tlie centre of the column ; as instructor, he goes wherever his presence is neces- sary. SJ5. The senior lieutenant takes post with the right platoon ; the next in rank with the left platoon ; the third with the sec- ond from the right, and the fourth with the second from the left. Each lieutenant is chief ol the platoon with which he is posted : and in line, and in column of platoons, is two yards in front of the centre of his platoon ; in column of detachments, each is on the side of the guide, or on the side towards which the subdivis- ions are dressed, two yards from the flank of the column, and opposite tiie centre of the platoon ; (they are always on the side opposite that of the gunners: par, 23;) in column of tiles, each as if he liad faced witii the battery from line, except tlie chief of the leading platoon, who takes post by the side of the leading guide. St6. The first-sergeant^ in line, is on the rigiit of the battery, aligned on the front rank and one yard from it; in column of platoons and of detaclmients, he is on the same side as the cliief- of-platoon, aligned on the front rank of the nearest subdivision and one yard from it; in column of files, he is as if he had faced with tlie battery from line. Wiien two or more batteries are united in line, he is as explained in {see Battalion). ^H, Each chief -of -detachment is on the right of the front rank of his detachment, as in par. 1;"). 28. Each gunner is two yards in rear of the centre of his de- tachment, except as provided in par. 16. 29. The trumpeters^ in line, are in one rank on the right of the first-sergeant, and two yards from liim ; in column of pla- toons and of detachments, they wheel to tlie side indicated, and are either four yards in front of the centre of tlie leading subdi- vision, or four yards in rear of the last subdivision, according as the column has been formed towards their flank of the battery, or the opposite ; in column of files, they are as if they had faced with the battery from line, and the one in rear stepped to the right, or left, of the other, according as they faced to the right or left. 30. The guides of a battery or platoon are the non-commis- sioned officers x>osted on its riglit and left ; the guides of a de- 8 PRELIMINARY INSTRUCTION. tachment are the chief-of-detachment and the front-rank man on the opposite flank. 31. Tlie chief s-of-detachnients and platoons give or repeat commands only when it is prescribed. This rule is general.* 32. For the purpose of instruction in marcliing drills the de- tachments are equalized, and should not consist of more than eight cannoneers. 33. When the battery faces about in line, the first-sergeant and the trumpeters face about, but do not change to the other flank. 34. When the nnnr>er of platoons and detachments are so reduced as to make surplus officers or non-commissioned officers, these take their places two j^ards behind the rear rank, and, with the gunners, act as file -closers; the ofticers, and likewise the non-commissioned officers, distribute themselves at equal dis- tances from right to left, according to rank. 35. It is the duty of file -closers to rectify mistakes, and in- sure steadiness and promptness in the ranks. 36. In all changes of formation, as soon as the movement permits, the officers and non-commissioned officers, whose posts are changed, hasten by the shortest routes to their posts in the new formation ; except, when in column of detachments, the detachments are wheeled about, they do not change, unless directed to do so by the instructor. To form the battery. 31. At the soimding of the assembly^ the first-sergeant, facing the battery and six yards in front of its centre, commands : 1. Fall in, 2. Left^ 3. Face, 4. Call rolls, 5. Report. The batter}?^ being divided into permanent detachments, as prescribed in par. 28, at the command fall in the chiefs-of- detachment place themselves on the line facing to the right, and at sufficient distance from each other for the formation of the detachments; the men of each detachment fall in, facing to the right, the front-rank men covering their chief; the sig- nal iiaving ceased, the first-sergeant causes, if necessary, the detachment to close up. At the command face., all face to the left. At the command call rolls., the chiefs-of-detachment step out two 5'^ards in front of the centres of their detachments, face towards them, call their rolls, and resume their places in the ranks. At the command report., the chiefs-of-detachment, standing fast, report to the first-sergeant, in succession from right to left, * See (e), Appendix 2. PRELIMINARY INSTRUCTION. 9 the results of their roll-calls ; the first-sergeant then commands : Call off, when each chief-of-detacliment steps promptly in front of his detachment and faces toward it to see that the men call oft' properly ; each man in turn calls out distinctly his num- ber — owe, two^ three^ and so on ; the gunner calls last — gunner. 38. If tlie front and rear rank contain an unequal number of cannoneers, the odd file is tlie left front-rank man, and the vacant space is in rear of him until after calling ott"; the left man of the rear rank then steps to his left and covers the left front-rank man ; he, however, retains his number, and at the piece takes the position belonging to it. The first-sergeant then faces about, salutes the captain, or other ofiicer acting in his place, reports the result of the roll- calls, and takes his position in line. 39. If, for marching drills or any other special purpose, the de- tachments are required of equal size, this is effected by transfer- ring men from the stronger to the weaker detachments ; but for ordinary service, such as marching to and from the place of exer- cise with the pieces, the detachments need not be of equal size.* 40. When a battery is to form for ordinary garrison pur- poses, such as fatigue duties. Or for roll-calls when the battery is small in numbers, the first-sergeant places iiimself six yards in front of the centre, facing towards the battery, and com- mands : Fall in. At the command yaZ^ in, the senior duty-sergeant places Iiim- self, facing towards the right, at the point where the right of the battery is to rest; the privates fall in, in two ranks, facing to the rigiit, the front-rank men covering the senior duty-sergeant. The second duty-sergeant takes his place in rear of the last front-rank man, and the other non-commissioned officers place themselves, facing in the same direction as the rest, in such positions as, when they face to the left, will bring them equally distributed along tiie line ; the first-sergeant commands : 1. Left^ 2. Face, when the men face to the left; he then calls the roll, reports, as in par. 38, and takes his post in lino ; at the same time the officers take posts. 41. If the battery is to exercise at marching drill., after being thus formed, the first-sergeant, before reporting, divides it into the desired number of detachments of equal size, and assigns the chiefs-of-detaclnnent and gunners to their respective detach- ments, who take their posts accordingl}^ The detaclnnents call off* as before. If the exercise is to be at the pieces, the detachments are told off' in sizes to suit the particulai* pieces, and the chiefs and gun- ners are assigned as before. See (a), Aj)pondix 2. 10 MARCHING MANCEUVRES. 42. The manoeuvres of a separate platoon are identical with those of a battery, the command platoon being substituted for battery. 43. The manoeuvres of a separate detachment are analogous to those of a battery, the command detachment replacing that of battery. The chief-of -detachment acts as instructor, and i& replaced on the right flank of the detachment by the gunner. 44. The captain, or in liis absence the next officer in rank, acts as instructor. 45. All movements not specially excepted may be executed in double time. If the movement be from a halt, or when march- ing in quick time, tlie command double time precedes the com- mand march ; if marching, this command is omitted. 46. Officers, wlieu on duty with men, will habitually wear their swords; when in r.mks, or when giving commands, the sword must be drawn. Instruction in the use of the sword is given in Light Artillery Tactics. 47. The trumpet signals and rules for using them are those prescribed in Light Artillery Tactics. 48. When artillery is armed, equipped, and serving as either cavalry or infantry, and organized into commands of these arms, it will conform to the formation and tactics prescribed, respectivelj'^, for these brandies of service. Marching Manceuyres. The following manoeuvres are those most essential, and gen- erally used by Heavy Artillery troops. The principles embraced in them will serve for more extended exercises. To open ranks. 49. Being in line, at a halt, the instructor commands : 1. Rear open order., 2. March, 3. Front. At the first command, the chiefs-of-detachment, and gunner acting as left guide, step brisklj'' three yards to tlie rear to mark the new alignment of tiie rear rank; the insti-uctor goes to tlie riglit flank and sees that these non-commissioned officers are on a line parallel to the front rank. 50. When the batterj?- is not divided into detachments, the non-commissioned officer on the right and left flanks, respect- ively, steps back to mark the line. At the command march., the chiefs-of-platoon step forward one yard, thus bringing themselves three yai'ds in front of the battery. Should there be officers in the line of file-closers, they MARCHING MANCEUVRES. 11 pass around the nearest flank and place themselves in the line of officers opposite their former positions. The front-rank men dress to the right ; the rear-rank men cast their e3^es to the right, step backwards, halt a little in rear of alignment, and then dress to the line established by the non-commissioned officers who have stepped back ; the file-closers step back at the same time, taking a distance of three yards from the rear rank. The instructor superintends the alignment of the chiefs-of- platoon and of the front rank, and tlie first-sergeant, or in his absence the chief of the right detachment, that of the rear rank; the instructor verities the alignment of the rear rank and of the file-closers ; the chief s-of-platoon and file-closers cast their eyes to the front as soon as their alignment is verified. At the command fronts the non-commissioned officers who have stepped back to mark the line for the rear rank resume their places in the front rank, and the men cast their eyes to the front; the first-sergeant returns to his post, and the instructor places himself six yards in front of the centre of the battery^ facing to the front.* To close ranks. 5SJ. Being at a halt, the instructor commands : 1. Close order ^ 2. MARCH. . At the command march^ the chief s-of-platoon face about and resume their posts in line ; the rear rank closes to facing dis- tance, each man covering his front-rank man; the file-closers move forward with the rear rank and take their posts in line ; the instructor resumes his post in line. Alignments. 53. Being in line, at a halt, with the ranks open, the in- structor establishes two or four men as a basis for each rank, at first in parallel and afterward in oblique directions to the front of the battery. He then commands : 1. By file^ 2. RigM (or left\ 3. Dress, 4. Front; or, 1. By jile^ 2. RigM (or left) backward^ 3. Dress, 4. Front; or, 1. Right (or left)^ 2. Dress, 3. Front; or, 1. Right (or left) backward^ 2. Dress, 3. Front. Each rank is aligned as explained in the School of the Soldier, the rear rank remaining parallel to the front rank. The ranks being closed, the alignments are repeated in the same manner. In all alignments, the file-closers preserve their distances from, the rear rank. * See (b), (c), (d), Appeadix 2. 12 MARCHING MANCEUVRES. To rest. 54. Being at a halt, the instructor commands : 1. Battery^ 2. Rest; or, 1. In place.^ 2. Rest. To resume attention, the instructor commands: 1. Battery^ 2. Attention. To dismiss the battery. 55. Being in line, at a halt, the instructor comm i:: Js : Dis- miss THE BATTERY. The officers return their swords and fall out; the first-sergeant then commands : 1. Break ranks ^ 2. March. To march in line, 56. The battery being at a halt, and correctly aligned, the instructor commands : 1. Forward., 1. Guide {right ov left)., 3. March. At the command forward., the guide selects two points on a line passing through him and perpendicular to the front of the batterj"; at the command march., the men step off with life ; the guide observes with the greatest care tlie length and cadence of the step, marches on the two points he has chosen, and selects others in advance on the same line before reaching the first ; the file-closers keep at their proper distances from the rear rank. To halt the battery and to align it. 5'y. The instructor commands : 1. Battery, 2. Halt, 3. Right (or left), 4. Dress, 5. Front. To march in the short step ; to mark time ; to change step ; to side step ; to march backward ; to oblique in line ; to pass from quick time to double time, and the reverse. Executed as explained in the School of the Soldier, substi- tuting, in the commands, battery for squad, wherever the latter occurs. 58. In the oblique march, the ranks remain parallel to their former position. 59. In marching in double time the left hand, instead of be- ing raised, steadies the scabbard ; the sword, if drawn, is held in a vertical position in the right hand. MARCHING MANOEUVRES. 13^ To wheel the battery. 60. Being in line, at a lialt, the instructor commands : 1. Right (or left) wheel, 2. March, 3. Battery^ 4. Hai^T, 5. Left (or right), 6. DRESS, 7. Front. At the command march, the battery wheels to the right on a fixed pivot; the left guide conducts the marching flank; the right guide stands fast, so that tlie breast of the pivot-man may- rest against his left arm at the completion of the wheel ; the chiefs -of -platoon face about at the first command, step back- ward at the second, and superintend tiie movements of tlieir platoons, resuming their positions at the command front; the instructor hastens by the shortest line to place himself directly in front of the pivot-guide, and at a distance from him equal to the length of the battery front, and faces to the late rear. At the command/mZ^, given when the left guide is three yards from the perpendicular, tlie battery halts; the left guide of the battery advances quickly, places his loft elbow lightly against the breast of the instructor, who establishes him on the line. At the command dress, the men dress up to the line of the guides; at the command y'ro/i^, the right guide places himself on the right of the pivot-man. 61. To continue the march upon the completion of the wheel, the instructor, without placing himself in front of the pivot- guide, commands : 3. Forward, 4. March, 5. Guide right (or left). The tiiird command is given when t he guide on the march- ing flank is three yards from the perpendicular to the original! front ; the fourth, the instant the wheel is completed ; and the fifth immediately after. The guide on the pivot places himself by the side of the pivot-man at the command /b?'warc?. 62. Marching in line, the instructor commands : 1. Right (or left) wheel, 2. March, 3. Forward, 4. March.. At the second command, the battery wheels to the right on a movable pivot ; the command forward is given when tiie guide is three yards from the perpendicular, and the fourth command; at the instant the change of direction is completed. In wheeling on a movable pivot, the command forward is given in sufficient time to add march the instant the wheel is comple- ted. This rule is general. 63. Marching in line, to eff'ect a slight change of direction, the instructor commands : ' Incline to the right (or left). The guide advances gradually the left shoulder, and marches- 14 MARCHING MANOEUVRES. in the new direction ; all the files advance the left shoulder and ■conform to the movements of the guide, lengthening or shorten- ing the step according as the change is towards the side of the guide, or the opposite. To march by the flank, 64. Being in line, at a halt, the instructor commands : 1. Right (or left\ 2. FACE, 3. Forward. 4. MARCH. If marching, the instructor commands : 1. By the right (or left) flank^ 2. March. The march in column of files is usually in quick time ; if neo- •essary to march in double-time, the distance between files is Increased to thirty-two inches, and, upon halting, the files close to facing distance. 65. To halt the battery, and form it in line, the instructor commands: 1. Battery^ 2. Halt, 3. Left (or right), 4. Face; or, to form line and continue the march : 1. By the left (or right) Jlank, 2. March, 3. Guide {right or left). To oblique and to change direction in column of files. Exe- cuted by the commands and means prescribed in the School of the Soldier. To form column of platoons to the right or left, 66. Being in line, at a halt, the instructor commands : Platoons right (or left) wheel, 2. March. At the first command, each chief-of-platoon, facing it, cautions it : Right wheel. At the command march, each platoon wheels to the right on a fixed pivot, as explained for the wheel of a battery. Each chief, superintending the wheel of his platoon, hastens to the point where the left of his platoon is to rest on the completion of the wheel; faces to the late rear, and when the marching flank approaches him, commands : 1. Platoon, 2. Halt, 3. Left, 4. Dress, 5. Front. At the command halt, the guide on the marching flank places his left arm against the breast of his chief, who then aligns the platoon and takes his post in front of its centre, after command- ing front. If marching, the movement is executed as just ex- plained, the pivot-guides halting at the command march, mark time in their places, and conform to the movements of the front of the platoon. 67. In every case where a line is broken in platoons, the MARCHING MANCEUVRES. 15 ^nner of the left detacliment of each platoon, if not already there, hastens to place himself on the left flank of his detach- ment as soon as the movement will permit; he then becomes the left guide of his platoon. Wlien the line is reformed, he hastens to resume his former position. 68. To form column of platoons to the right or left and con- tinue the march instead of halting, the instructor commands : 1. Continue the marcli^ 2. Platoons right (or left) wheels 3. March, 4. Forward, 6. March, 6. Guide {right or left). The movement is executed as before, except that each chief remains in front of the centre of his platoon, and the platoons move straiglit forward at the fifth command. The leading guide prolongs accurately his line of march hj choosing successively points in advance ; the other guides preserve with care the trace, the step, and wheeling distance. To put the column of platoons in march, and to halt the column. 69. The instructor commands : 1. Forward, 2. Guide {right or left), 3. March, and 1. Bat- tery, 2. Halt. To form line to the right or left from column of platoons. TO. Being at a halt, the instructor commands : 1. Right (or left) into line wheel, 2. March, 3. Battery, 4. Halt, 5. Left (or right), 6. Dress, 7. Front, 8. Guides, 9. Posts. At the first command, each chief-of-platoon, facing it, cautions it : Right wheel. At the command march, the pivot-guides stand fast in their places and the platoons wheel to the right on a fixed pivot. At the command halt, given when the marching flanks arrive near the line, the subdivisions halt ; the instructor places himself, fac- ing to the right, on the prolongation of the line of the pivot-guides, at the point where the marching flank of the leading subdivision is to rest. At the command dress, the battery dresses up to the line established bj' the pivot-guides and instructor, the left guide of the leading subdivision touching the breast of the instructor •with the left arm; the instructor superintends the alignment, and gives the commund front upon its completion. At the com- mand guides posts, the guides return to their places in line. If marching, the movement is executed as just explained, •except that, at the command march, the guides and pivot-men 16 MARCHING MANCEUVRES. halt ; the pivot-men mark time and turn in their places, so as to conform to the movement of the marching flank. f 1. To form line and continue the marcii, the instructor commands : 3. Forward^ 4. March, 5. Guide {right or left). At the Q,ou\uiB,Vi(\. forward^ tlie pivot-guides take their places in line* To form line to the front column of platoons. 72. Being at a halt, the instructor commands : 1. Right (or left) front into line, 2. MARCH, 3. Front. At the first command, the chief of the leading platoon com- mands : 1. Forward, 2. Guide left; the other chiefs command : Right oblique. At the command march, repeated by all the chiefs, the leading platoon advances eighteen yards, when its chief commands: 1. Platoon, 2. Halt, 3. Left, 4. Dress; the other platoons oblique to the right until opposite their places in line, when their chiefs command : 1. Forward, 2. March, 3. Guide left, adding, as they arrive near the line : 3. Platoon, 4. BLalt, 5. Left, 6. Dress; the instructor superintends the align- ment from the left flank, and gives the command yVon^ upon its completion. If marching in quicJc time, the movement is executed as just explained, the chief of the leading platoon commanding guide left, if the guide be not already there. If marching in quick time and the command be double time, the instructor commands : Guide left immediately after the com- mand march; the chief of the leading platoon does not halt it, but cautions it to advance in quick time, and repeats the com- mand for the guide ; each of the other chiefs repeats the com- mand double time, and, when his platoon is about to arrive in line, commands: 1. Quick time, in time to add: 2. March, the instant it arrives abreast of the leading platoon. If marching in double time, the chief of the leading platoon commands : Quick time at the first command, and repeats the other commands; the other subdivisions complete the movement as before. To form column of platoons from column of files. •yS. The instructor commands : 1. Platoons, 2. Right (or left) front into line, 3. March, 4. Bat- tery, 0. Halt. At the command march, the leading guide of each platoon moves straight to the front; all the files oblique to the right until opposite their places in line, when each marches to the front. MARCHING MANCEUVRES. 17 The leading guide of eacli platoon moves forward until the command halt^ which is given when he has advanced live yards ; the other men halt on arriving in line ; each guide in rear places himself on the right of the front rank upon the arrival of the last file; the leading guide having halted, each chief dresses his platoon to the left, and commands : Front when the last file is aligned. If the command be double time^ the instructor commands : Guide left (or right) immediately after the command march j the leading guide of each platoon moves forward in quick time ; tlie other men oblique in double time, each taking the quick step and dressing to the left upon arriving in line; the rear-rank men then close to facing distance. This movement is not executed when marching in double time. The instructor's command is right (or left) front into line^ according as the column of files is left, or right, in front. T4. The column of files is right in front when the front-rank men are on the left of their rear-rank men ; it is left in front when the front-rank men are on the right of the rear-rank men. To change direction in column of platoons. 75. Being in march, the instructor commands : 1. Column right (or left), 2. March. At the first command, the chief of the leading platoon com- mands : Right wheel; at the command march, which he repeats, his platoon wheels to the right on a movable pivot, the chief adding : 1. Forward, 2. March, upon tlie completion of the wheel ; the other platoons march squarely up to the wheeling point, and change direction by command of their chiefs as ex- plained for the first. 76. In wheeling on a movable pivot, as the dress is always toward the marching flank without command, whenever a Avheel is executed toward the side of the guide, each chief, upon its completion, cautions his platoon, guide right, or guide left, ac- cording as the guide was right or left before the wheel. 77. In changing direction, each chief-of-platoon faces his platoon while wheeling, and sees that the guide takes steps of twenty-eight or thirty-three inches, and the pivot, steps of nine or eleven inches, according to the gait. Column half right (or half left) is similarly executed, each chief giving the preparatory command right (or left) half wheel. To make a small change of direction, the instructor cautions : Incline to the right (or left). 2 18 MARCHING MANOEUVRES. The leadin.^ guide advances his left shoulder and takes two points a little to the right of those upon which he was mai'ching, the men conforming to tlie new direction of the guide. 78. To put the column of platoons in march and change direction at the same time, the instructor commands : 1. Forward^ 2. Guide {right or left)^ 3. Column right (or left)^ 4. March. To face the columii of platoons to the rear^ and to march to the rear. '^'9. Tlie instructor commands : 1. Platoons inght (or left) .about^ 2. March, 3. Battery^ 4. Halt. At the command march^ the platoons execute an about on a fixed pivot; at the command halt^ each chief-of-platoon dresses his platoon to the left, commands : Front, and then takes his post. To march to the rear after wheeling about, the instructor com- mands : 3. Forward, 4. March, 5. Guide {left or right). To form column of detachments to the right or left. 80. Being in line, the instructor commands : 1. Detachments right (or left), 2. March. At the first command, the gunner, acting as left guide of the battery, falls out and takes his place in rear of his detachment ; at the command march, each detachment wheels to the right on a fixed pivot ; upon the completion of the wheel, the front rank of each take the full step (28 inches) ; the rear rank shortens the step till it gains the distance of thirty-two inches from the front rank ; the guide and dress of each detachment is, without fur- ther command, towards the side opposite the gunners, i. e., to- ward the wheeling flank; the leading guide prolongs accurately his line of march by choosing successively points in advance ; the other guides preserve with care the trace, the step, and wheel- ing distance. The gunners march one yard from the flank of their respective detachments, and see that the ranks maintain accurately their alignments and distances. The positions of the officers, first - sergeant, gunners, and trumpeters are as prescribed in pai^s. 26 to 33. MARCHING MANCEUVRES. 19 To form column of detachments and halt. 81. The instructor commands : 1. Detachments right (or left)^ 2. March, 3. Battery., 4. HALT. The fourth command is given the instant the front ranlc com- plete the wheel ; the rear ranks fall back to thirty-two inches, and all the ranks dress, without further command, toward the marching flank. 82. In all wheelings by detachments, the forward march is taken upon the completion of the movement, unless the com- mand halt be given. This ride is general. 83. In column of detachments, the ranks dress toward the flank opposite the gunners. This 7mle is general. To march in column of detachments to the front from either flank. 84. Being in line, the instructor commands : 1. Right (or left) forward^ 2. Detachments right (or left)., 3. March. At the command march., the right detachment moves straight to the front, with the guide to the left ; its rear rank, shortening the step, falls back to thirty-two inches ; the other detachments wheel to the right on a fixed pivot ; the second detachment, when its wheel is nearly completed, wheels to the left on a movable pivot, and follows the first detachment ; the other de- tachments having wheeled to the right, move forward and wheel to the left on a movable pivot on the same ground as the second. Being in column of detachments., at a halt or marching., to change the chief s-of-platoons and gunners from one fla7ik of the col- umn to the other. 85. The instructor commands : 1. Officers and gunners change flank., 2. MARCH. At the first command, the officers and gunners close into the flanks of the column; and, at the command march., pass quickly through the column between the detachments. To put the column of detachment in march., and to halt the column. 86. The instructor commands : 1. Forward., 2. MARCH, and 1. Battery., 2. Halt. 20 MARCHING MANCEUVRES. To change direction in column of detachments. Being in march, the instructor commands : 1. Column right (or left)^ 2. March. At the command marc\ the leading rank wheels on a movable pivot ; the wheel being completed, this rank retakes the step of twenty-eight inches ; the other ranks move forward and wheel on the same ground. Column half right (or left) is similarly executed. ST". To put the column of detachments in march, and change direction at the same time, the instructor commands : 1. Forward^ 2. Column right (or left)^ 3. March. To marcJi the column of detachments to the rear. 88. The instructor commands : 1. Detachments right (or left) about ^ 2. March. The detachments wheel about on a fixed pivot ; the man on the marching flank of the rear rank of each detachment pre- serves the distance of thirty-two inches from his front-rank man ; the man on the pivot flank closes up to his front-rank man, covering him during the wlieel, and on its completion falls back to thirty-two inches; tlie chief s - of - platoon and the gunners oblique to the right or left in turning about, so as to preserve their proper positions with reference to the column. To form line from column of detachments. 89. To the right or left. Thebatterybeingat a halt, or march- ing, the instructor commands : 1. Detachment right (or left)., 2. March, 3. Guide {right or left)'., or, 3. Battery^ 4. HAliT, 5. Left (or right)^ 6. Dress, 7. Front. At the command march., the detachments wheel to the right on a fixed pivot. The rear rank of each detachment closes to facing distance during the wheel, except when executed in double time, and the line advances on the completion of the wheel. If the line be formed towards the side from the chiefs-of-pla- toon, they close to the flank of the column at the first command, and, at the command march, pass quickly through the column between their detachments; the gunners, at the same time, in like manner, pass to the other side of the column. When the command halt is given, tlie instructor; before dress- ing the battery, places the leading guide on tlie line of the pivot- MARCHING MAN(EUVRES. 21 men, and at a distance* from the leadin of the gun in which they are used, and have not as Prismatic. J yet been definitely determined upon in our service. Specific gravity. The specific gravity of gunpowder varies from 1.65 to 1.8. It is important that it should be determined with accuracy. Alco- hol, and water saturated with saltpetre, have been used for this purpose; but they do not furnish accurate results. Mercury only is to be relied upon. Hardness is tested by breaking the grains between the fingers, and is judged of only by experience. Muzzle^ or initial velocity. This is determined by any of the electro-ballistic machines available ; the Boulong^ chronograph is one of the simplest and most generally used for proof of powder. For a full description and use of the instrument, see Ordnance Memoranda, No. 25. Strain upon the gun. This is determined by the Rodman pressure-gauge. For de- scription and use of the instrument, see Ordnance Memoranda, No. 25. Determination of moisture and resistance to moisture. The amount of moisture in powder is determined by drying samples in an oven with a water bottom. The powder is subjected to heat as long as it loses weight, the loss indicating the percentage of moisture driven off. On being removed from the oven it should be transferred at once to per- fectly clean, dry, air-tight weighing bottles. Tlie ability to resist moisture is determined by subjecting samples which have been dried to exposure, first in open air, then in a hygroscope containing a solution of nitre at 100° cooled to 80° Fahr. Tile hj-^groscope is an air-tight box in which the powder is 44 GUNPOWDER. subjected to a damp atmosphere at a uniform temperature for 24 hours. The powder to be tested is placed in circular cups of copper with fine wire-gauze bottoms, affording free access of moisture to all parts of the sample under test. The percentage of gain is determined by weighing the powder in carefully-prepared bottles on opening the hygroscope. A careful record is kept of the barometer, hj^grometer, external, and maximum and mini- mum internal .thermometers. Incorporation. On breaking the grains, a fine uniform ashen-gray color throughout should appear; the grain texture should be close, without white specks even when magnified. For "flashing" on glass or porcelain plates, the powder should be in small conical heaps. Small copper measures for fine-grain powders, inverted on the plates, keeps the heap nearly the same at each trial. If the incorporation is good, only smoke marks remain on the plate after flashing ; if bad, specks of undecomposed nitre and sulphur will form a dirty residue. The test requires experience to insure success. Inspection report. The report of inspection should show the place and date of fabrication and of proof, the kind of powder and its general qualities, as the number of grains in 100 grs. ; its specific grav- ity ; whether hard or soft, round or angular, of uniform or irreg- ular size; whether free from dust or not; the initial velocities and pressures per square inch obtained in each fire ; the amount of moisture absorbed ; and, finally, the height of the barometer and hygrometer at the time of proof. Marks on the barrels. Each barrel is marked on both heads (in white oil-colors, the head painted black) with the number of the barrel, the name of the manufacturer, year of fabrication, and the kind of powder, cannon^ mortar., or musket^ &c., the mean initial velocity, the pressure per square inch on the pressure-piston, and density. Each time the powder is proved, the initial velocity is marked below tlie former proofs, and the date of the trial opposite it. Each barrel contains 100 pounds. SPECIAL POWDERS. 181. For some years it has been a recognized fact that the ignition, combustion, and explosive effect of gunpowder depend, GUNPOWDER. 45* in a great degree, on the size, shape, and density of the grain, and that guns of different calibres require for their most efficient service powders differing in these features, in order to secure the best results. The rapid increase in weight of projectiles with the increase in calibre of guns, and the comparatively smaller power of resistance of the guns, renders it necessary that the rate of combustion of the charge be regulated so as to reduce the strains on the guns as much as possible, while at the same time preserving high initial velocity to the projectile, thus ren- dering practicable the use of the heaviest guns, projectiles, and charges. The amount of gas evolved at the first instant of inflammation and combustion is measurably controlled by the size and form of grains, offering a lesser surface of ignition, and the increased density, offering greater resistance to the penetration of the hot gases through the grains, graduates its rapidity of burning. The form of grain affecting the amount of surface exposed to com- bustion — that shape which offers a comparatively small surface at the first instant of ignition, increasing progressively — is theo- retically the best. Expei-iments have settled the important part plaj'^ed by pow- ders suited in the above qualities to the guns in which they are to be used, and have led to the adoption of large-grain powders in heavy guns, resulting in the production, among the best, of mammoth, pebble, cubical, hexagonal, and perforated prismatic powders. {Figs. 4, 5, 6, 7, Plate IV.) Hexagonal powder. This powder has been found to give the best results when used in pieces of heavy calibre. The uniform size of grain, and their polyhedral shape, insure great uniformitj' in position and size of the interstices in the make-up of the cartridge ; this in- sures, with a uniform density of grain, a high degree of uniform- ity in pressures and velocities from given charges of powder and weights of projectiles. The powder used is composed of United States standard proportions of the ingredients, with a specific gravity of 1.7511. Its shape and dimensions are given on Plate IF, Figs. 8, 9. The proportions of tlie ingredients of hexagonal powder con- form to the United States standard, and up to the completion of the incorporation in the wheel mill, its manufacture is like that of ordinary powder. Mealing. The wheel mill cake is revolved in a cylinder of wire- wove cloth, with wooden balls, until it is mealed. Pressing. The mealed powder is then carefully pressed be- 46 GUNPOWDER. tweeii horizontal metallic plates or dies. The powder comes out in a sheet or cake of polj^hedral granules united along their vertical edges, the dies being nearly perfect dodecahedrons. Graining. The press-cake is passed between rollers armed with brass cutting teeth at an angle of from 60° and 120° to the axis, which cut the cake into granules, their cross-section being almost hexagonal, whence the powder derives its name. The powder is then sent to the glazing-mill and glazed ; after which it is brpshed and dried. The powder is now minutely- examined, its specific gravity taken, and a count made of the granulation ; a variation of two granules to the pound is enough to condemn the powder, the granulation being 72 to the pound. It is packed in barrels in the usual manner, and is fired in car- tridge-bags as other powder. Mammoth poioder. This powder is formed by breaking up mill cake. Exact uni- formity of size and shape of grains does not therefore exist. The average granulation is 85 to the pound. {Fig. 3, Plate IV.) Prismatic powder. This variety is formed by pressing mealed powder into prisms. The hexagon is usually adopted, as it offers a good shape for piling, and the angles are sufficiently obtuse to prevent spawl- ing at the edges. In order to insure uniform and progressive combustion, each prism is perforated with a small hole through its axis; formerly several holes were pierced. Cubical powder. This powder is of a regular cubical grain, being formed by cutting press-cake in two directions at right angles to each other. Each grain is 0.75 inch in size. The granulation is about 72 to the pound. {Fig. 4, Plate IV.) It is important to observe tliat the proper kind of powder is used in the guns for which intended. 182. The system of classification in use in the ^N'avy differs somewhat from that employed in the Army. The hexagonal, cubical, and mammoth are about the same; but N^avy rifle cor- responds nearly to Army cannon., and the N^avy cannon is the nearest equivalent to Arm}^ mortar. In exchanging powder witli the IN'avy, it is necessary to ob- serve these distinctions. Powder barrels should never be openedyCxcept when required for use, as grains of powder falling between the staves would PROJECTILES. 47 prevent their being tightened. Samples must be taken from the buno-. 183. For ordinaiy examination, the flashing test^ heretofore mentioned, is a ready way of ascertaining- whether the powder is of good quality and in good condition. If powder has been much damaged by damp it will be caked, and a close inspection will generally detect a white appearance on the grains, due to nitre having been dissolved and deposited in crystals on the surface. Powder sometimes becomes caked by being tightly packed in cartridges, or for want of being rolled when in barrels. It will then readily crumble into its original grains by being pressed in the hand ; but if the grains break or appear friable, the powder is unfit for service. This latter characteristic indicates that the caking has resulted from dampness, and is to be carefuU}' distinguished from the former. Fressure, 184. The pressure of gunpowder, when fired in its own space, is placed at about 95,000 pounds to the square inch. When, how- ever, the powder gas expands in the bore of the gun, though the proportion of the products of combustion are the same, the ten- sion is greatly less. 185. Cartridge-bags are sacks for containing charges of pow- der when put into the piece. They should be made entirely from either woolen or silken stuff; the fabric should be soft, and closely woven, to prevent the powder from sifting through. The seams should be sewed with woolen 5^arn or silk. Pkojectiles. 186. Projectiles for the U. S. artiller}'' service are made of cast-iron, a material combining in a greater degree than any other the essential qualities of hardness, strength, density, and cheapness. Projectiles are classified as spherical and elongated. The first are used exclusively in smooth-bore guns ; the second in rifles. They are furtlier classified, according to their structure and mode of operation, as solid^ hollow^ and case-shot. 18'V. Solid projectiles produce tlieir eftect from impact alone, and as they can be fired with the greatest charge that the piece will bear, are used when great range, accuracy, and penetration are required. They are the only projectiles that can be used with effect against very strong walls, or armor-plated vessels. 48 PROJECTILES. Under the head of hollow projectiles are included shells for gims, howitzers, and mortars. 188. Shells have less strength to resist shock from the dis- charge of the piece and from impact ; they are therefore gen- erally iired with smaller charges of powder than solid shot. The weight of a shell is generally about two-thirds that of a solid shot of the same calibre. They are charged with mortar powder, which, exploding with violence, produces great destruc- tion to both animate and inanimate objects. The principal parts of a shell are : First. The cavity., used to hold the bursting charge ; or burst- ing charge and incendiary composition, when the intention is to destroy by setting fire to objects. Second. The fuse-Jiole^ which is used for inserting the charge, and to hold the fuse whicli communicates fire to it. Spherical shells have two small shallow holes, one on each side of the fuse-hole, into whicli are inserted the shell-hooks when loading. These holes are called eai^s. Shells for mortars, being fired with lighter charges than those for guns, have less thickness of metal. Spherical shells for guns are reinforced on the inside, around the fuse-hole, to prevent the fuse-plug from being driven in b}'' the force of the discharge. This reinforce serves, in some meas- ure, to compensate for the loss of weight on that side of the shell caused by the fuse-hole, thus rendering the shell more accurate in flight. 189. Case-shot is a projectile similar to a shell, but with much less thickness of metal. It is filled with leaden bullets, which are secured against moving loosely about by having their interstices filled with melted sulphur. Through the fuse-hole, a hole is bored into this mass of bullets and sulphur sufficient to contain a bursting charge. This projectile is intended only for use against troops. The fuse is so regulated as to burst the shell a short distance in front of the object, when the bullets and fragments, separating, move forward in a sheaf form, and pro- duce effect as from musketry. The charge for case-shot should be only sufficient to rupture the case. 190. Elongated projectiles are used exclusively for rifle guns, and, like the spherical, may be either solid or hollow. There are in service various patterns, each known, genorally, by the name of the inventor. They all, however, have a general re- semblance to each other, and consist of a cylindrical body sur- mounted by a conoidal head. To the base is attached a ring or cup of some softer metal, which, expanding from the force of PROJECTILES. 49 the discharge, enters the grooves of the piece and causes the pro- jectile to take a rotary motion about its axis. The fuse-hole, which is in the pointed end, is coincident with the axis. The fuse-plug is screwed into the fuse-hole. The most approved pattern is known as the Butler projectile, {Fig. 1, Plate F,) the sabot of which consists of a bronze ring screwed upon the base. In this ring an aiuiular groove is cut ; the gas from the charge acting on this channeleur forces the exterior lip into the grooves of the bore, while the interior is forced still tighter upon the body of the projectile, thus prevent- ing it from stripping. 191. A cored shot is an elongated projectile having a cavity in the body of it. This cavity is for the purpose of throwing the centre of gravity towards the front end of the projectile, thus insuring greater steadiness of flight. The hollow projectiles are either shells or case-shot, both of which, in their construction and use, are similar to those hereto- fore described for smooth-bore guns. Rifle projectiles have a length of two to three times their diameter, depending upon the pattern, and whether solid or hollow, the latter being generally the longest. 192. A canister is a projectile consisting of a hollow tin cyl- inder filled with cast-iron or leaden balls, which vary in size and number with the kind and calibre of piece. The cylinder is closed at the bottom with a thick cast-iron plate, and at the top by one of sheet iron. The balls are packed in with dry sawdust. Canister is not effective at a greater distance than 400 yards, and, with the exception of flank howitzers, is but little used for heavy artillery. 193. Grape-shot. A stand of grape is composed of nine cast- iron balls, disposed in three layers of three balls each. They are held together by two circular iron plates, united by a bolt passing through their centres. Around this bolt the balls are held by two iron rings. The plates have a diameter correspond- ing to the calibres of the gun in which the grape is to be used. The size of the balls depends, likewise, upon the calibre of the gun. Grape is not fired from rifle guns, and has but limited use for those of smooth-bore ; the modern musket and Gatling being much more effective than either canister or grape. 194. A carcass is a spherical shell, having three additional holes, of the same dimensions as the fuse-hole, pierced at equal distances apart in the upper hemisphere of the shell. The shell is filled with a composition which burns, with intense power, from eight to ten minutes, and the flame, issuing from the holes, ' 4 50 FUSES. fires whatever is combustible within reach. It is used in bom- bardments for setting lire to shipping, magazines, camps, &c. When the prepared carcass is not to be had, a common shell, either spherical or elongated, may be substituted bj'" placing in the bottom of it a bursting charge contained in a bag ; over this, carcass composition is driven until the sliell is nearly tilled ; four or five strands of quick-match are then inserted, and secured by driving more composition upon them. These shells, after burn- ing as a carcass, explode. Port-fire composition is suitable for filling them. ' 195. AJire-hall is a projectile of an oval shape, formed of a sack of canvas filled with combustible composiUon, which, in burning, emits a bright fl.ame. It contains a loaded shell, and is used for lighting up the enemy's works. It is fired from a mortar. Fuses. 196. A fuse is the contrivance for igniting the charge of a hollow projectile, after it has left the piece, upon being fired. They are divided into four classes, viz.: the time-fuse, the percussion-fuse, the concussion-fuse, and the combination-fuse. 191". The time-fuse^ now used for heavy artillery, is com- posed of a paper case inclosing a column of compact composi- tion, which is ignited by the flame from the charge in the piece. It burns for a certain time, at the end of which it communicates the flame to the charge in the projectile. The paper case is made slightly conical to insure a close fit and to prevent it from being driven through and into the projectile. It is inserted, at the time of loading the piece, into a metal or wooden fuse-plug pre- viously driven or screwed into the fuse-hole of the projectile. The composition has the same ingredients as gunpowder, the proportions being varied to suit the required rate of combustion. To insure ignition, it is primed at the larger end with rifle pow- der. They are furnished from arsenals in water-proof packages, each package being marked with the number of seconds required for the burning of the fuse ; this time varies from twn to twenty seconds per inch. The paper case is graduated into seconds, which enables the fuse to be cut to a length corresponding to any intermediate time. All fuses of this kind are of the same diameter and are two inches in length. When it is to be used for ricochet tiring, especially over water, a plug, known as the water-cap fuse-plu^, is used. This is con- structed to prevent the burning composition from being extin- guished when the projectile strikes, and consists of a brass plug PRIMERS. 51 ■firmly driven or screwed into the fuse-hole of the projectile; the paper fuse is inserted at the time of loading the piece, after wiiich a water-cap is screwed into the plug. The water-cap is of brass, and is perforated with a crooked channel, tilled with mealed powder; the mealed powder com- municates fire to the paper fuse, and the angles of the channel break the force of the -water or dirt. The top of the cap has a recess filled with a priming of mealed powder, covered by a pro- tecting disk of lead or paper, which is pulled off immediately before inserting the projectile into the piece. For security against accidental ignition, a small leaden plug is placed in the Inner end of the fuse-plug, where it remains until it is driven out by the shock from the discharge of the piece. Fuse-plugs for mortar shells are generally turned from some hard wood ; these are made to fit closel}^ by rasping them off to the exact size. The paper time-fuse is used for either smooth-bore or rifle pieces. 198. The percussion-fuse is used only for rifle projectiles, and is ignited by the striking of the point of the shell against an object. There are many varieties of this fuse, all consisting, essentially, of a brass or pewter fuse-plug containing a plunger. This plunger does not move in its place until the sudden arrest- ing of the shell, by striking, causes it to break its fastening, and, by its inertia, is driven against a priming of fulminate, which, •exploding, communicates flame to the charge of the shell. 199. The concussion-fuse is made to operate by the shock of the discharge of the piece. There are also manj'^ varieties of this kind of fuse, all of which are composed essentially of a plunger, which, by its inertia, when the shell starts to move in the bore, breaks its fastenings, and, striking against a priming of fulminate, explodes it and communicates fire to a time-fuse inclosed in the same fuse-plug. The time-fuse is cut or set to burn the required time ; it then communicates flame to the eharge in the shell. Concussion-fuses are seldom used except for rifle projectiles. The combination-fuse is one combining the principle of action of the three former. There are, also, a great variety of this kind of fuse, all of which are more or less complicated. Primers. 200. The friction-primer is a device for communicating fire through the vent to the charge in the piece. It is composed of two brass tubes soldered together at right angles. The shorter 52 SABOTS. tube contains a small quantity of friction composition, in contact with whicli, and contained also in the short tube, is a serrated' wire, which wire is doubled at its other extremity into a loop forming an ej^e for the hook of the lanyard; the long tube is filled with rifle powder, and has its lower extremity closed with wax. {Fig. 2, Plate V.) The long tube is inserted in the vent; a pull upon the lanyard disengages the serrated wire, which, by its friction upon the composition, causes the latter to ignite, and thus communicating fire to the rifle powder in the long tube, explodes the cartridge in the piece. The charge of rifle powder has suflScient force to pass the flame through the longest vent and penetrate several thicknesses of cartridge-cloth. {Fig, 3, Plate V.) 201. The electric-primer 'is, an invention for firing cannon by means of electricity. It consists of the long tube of the friction- primer split at one end to receive a short but larger piece of brass tube, to which it is soldered. The larger piece incloses a cylin- drical piece of hard wood, slotted midway of its length and per- forated at each end to receive short pieces of copper wire, which are connected across the slot by a coiled piece of fine platinum wire. The outer ends of the copper wires project a few inches to connect the wires of the primer with the terminal wires of the battery. When thus connected, the batter}'' current heats the platinum sufficiently to ignite a small piece of loose gun- cotton, which, together with the platinum wire, occupies the slotted portion of the wooden cylinder. The ignited gun-cotton communicates flame to the powder in the long tube. '20S. Sabots are circular blocks of wood, fastened with tini straps to iiollow projectiles for smooth-bore guns. Their object is to prevent the projectile from turning in the bore and bring- ing the fuse in contact with the charge of the piece. The diam- eter of the sabot corresponds to that of the projectile ; it has a shallow dish-shaped cavity for the projectile to rest in, and is always attached to the side opposite the fuse-hole. When the piece is flred, the fragments of the sabot fly a short distance from the muzzle ; consequently it is dangerous to use this kind of ammunition when firing over the heads of our own troops. Owing to the liability of premature explosions, the same objection applies to hollow projectiles of every variety. The metallic ring, or cup, attached to the base of rifled project- iles for the purpose of expanding into the grooves of the piece and giving rotary motion to the projectile, is also called a sabots IMPLEMENTS. 53 BIPLEMENTS. 203. Implements for artillery are those instruments employed In loading, pointing, and firing cannon, and in mechanical ma- noeuvres therewith. Equipments are those things used for the same object, but which are carried by tlie individual men. S04. Gunner''s quadrant {Fig. 10, Plate IV) is an instrument for giving elevation or depression to a piece. It consists of a graduated quarter of a circle of sheet brass, of six inches radius, attached to a straight brass bar twenty-two inches long. It has an arm carrying a spirit-level at its middle, and a vernier and clamp screw at its movable end. The arc is graduated to half degrees, and the vernier reads to five minutes. To get a required elevation, the vernier is set at the indicated degree ; the brass bar is next inserted in the bore parallel to the axis; the piece is then elevated or depressed until the level is horizontal. The elevation may likewise be obtained by applying the bar to the face of the piece, care being taken to have it in a plane parallel to the plane of fire. The latter is the mode of using it with mortars. The difficulty of applying the quadrant to the muzzle of guns, especially to those in embrasure, has suggested that a metallic ledge be attached to the end of a trunnion ; upon this ledge the bar of the quadrant is applied when the elevation is to be given. The top of the ledge is parallel with the axis of the bore. 205. Gunner''s level is an instrument for marking the line of metal on a piece. Until within a very recent period it was re- quired with all pieces, but since the application of sights to guns its use is confined solely to mortars ; and owing to the fact that these pieces are left rough and unturned on the exterior, the line of metal marked, in the usual manner, with the gunner's level and a chalk-line, is, at best, but a crude and imperfect method of obtaining a line of sight. {Fig. 11, Plate lY.) The method of using this instrument is readily understood by an inspection of it. Sponge. This is a woolen brush, attached to a stafi*, used in cleaning the bore of cannon, and for extinguishing an}'- burning fragments of cartridge that may remain after firing. For field pieces the sponge and rammer-heads are on the opposite ends of the same staff"; for siege and sea-coast pieces they are attached to separate staves. With pieces of less than eight inches calibre the sponge-head <5onsists of a cylindrical block of wood about three calibres in length ; upon this is tacked the woolen stuff" forming the sponge. For pieces of larger calibre a spring-head {Fig. 4, Plate V) is used. This consists of three pieces of sheet iron, so fashioned as 54 IMPLEMENTS. to form, when put too^ether, a semi-ellipsoid corresponding to the- bottom of the bore of the piece for which intended. To these plates is attached the sponge material, which is secured bj^ pack- thread stitching through holes in the iron. Each plate is at- tached to the staff by a steel strap ; these by their spring allow the plates to close together and enter the bore with a tight fit. The necessary size is thus secured without the greater weight of solid wooden heads. Sponges are protected from the weather by canvas covers, which are painted. They are preserved from moths by the same means used for cartridge-bags. {Par. 568.) The rammer. This is used for shoving the cartridge and pro- jectile to their place in the bore of the piece. For small calibres the head of the rammer is a short cylindrical piece of tough wood, fixed to the end of a staff"; for the larger calibres it consists of a wooden ring bound with iron or copper and attached to the staff b}' three iron prongs or straps. (Fig. 5, Plate V.) This secures lightness with the necessary size. The ladle is a copper scoop {Fig. 6, Plate V) attached to a staff. It is used for scooping out the powder of a cartridge which maj'" have become broken when withdrawing it from the bore. The worm {Fig. 7, Plate V) is a species of double cork-screw attached to a staff, and is used for withdrawing cartridges from pieces. The pass-box is a wooden or metallic box M^ith a lid and han- dles, used for carrying cartridges from the service magazine to the piece. The boxes are of varioii.s sizes to suit the calibre of the piece, one cartridge being carried at a time. The budge-barrel is a barrel, to the top of which is attached a leather cover, which is gathered with a draw-string like the mouth of a satchel. It is used with pieces requiring small-sized cartridges, to carry them from the magazine to near the pieces to be served. The priming-wire is used to clear the vent and prick a hole in the cartridge. This latter is not, however, an absolute essential, as the explosion of the primer, as now made, will, with ordinary cartridges, carry flame to the powder. The vent-gimlet is a long gimlet for removing obstructions from the vent. The vent-punch is an instrument for the same purpose. As these instruments are made of hardened steel, great care must be observed in using them, that they do not break in the vent and spike the piece. The fuse-setter is a brass drift for driving wooden fuse-plugs into shells. IMPLEMENTS. OD Fuse-wrench is a three-pronged wrench used for setthig fuse- phigs that are to be screwed uito the shell. One prong con- tains forks for the fnse-plng, and another one smaller forks for the water-cap. Fuse-block^ sometimes called fuse-gauge, {Fig. 8, Plate F,) is a simple contrivance for holding paper time-fuses when being cut. It consists of two blocks of wood lunged together so as to open and shut after the manner of a book. In each end is a recess into which the fuse is placed, and whore it is securely held by pressing the blocks tightly together. The fuse is put in with the small end extending out of the end of the block, the point at which it is to be cut being even with the end of the block. Along one side of the recess is attached a brass scale. This was intended for fuses of obsolete pattern. As now made, each fuse is divided into as many equal parts as the number of sec- onds for which its entire length (two inches) is intended to burn. These parts are marked, and are the guides in cutting the fuse ; the latter operation being performed with the fuse-knife^ which is a sharp thin-bladed knife, (preferably a shoe-knife,) or a fine saw. (See Fuses, ^ar. 196.; Fuse-plug extractor. This is an instrument for extracting fuse-plugs after they have been driven. It is a stout screw, which may be screwed into the fuse-hole of the plug, which is then pulled out by means of a screw operating after the manner of certain kinds of cork-screws. Fuse-reamer is used to enlarge the hole in a fuse-plug so as to make it of proper size for the paper fuse. Powder-measures are made of copper, of cylindrical form and of various sizes, for the purpose of determining the charges for shells and cannon by measurement. Each measure is marked with the weight of mortar powder which it holds. They come in sets, holding from one ounce up to several pounds, and fit together in a nest. Lanyard is a strong cord, one end of which has a small iron hook and the other a wooden handle. It is used for exploding the friction-primer when a piece is to be fired. Shell-hooks is an implement constructed to fasten into the ears of a shell for the purpose of lifting it to the muzzle of the piece. Gunner'' s pouch and pi'imer-pouch are made of leather, and are attached to the person by a strap buckling around the waist. Cartridge-pouch is made of leather, and is carried suspended from the shoulder to the opposite side. It is used when small cartridges are required, for carrying them from the magazine or budge-barrel to tlie piece. OG MOTION OP PROJECTILES. Sight-pouch is a long, slender case, used sometimes for carry- ing the breech sight. It is suspended from the shoulder. Handspikes. With siege guns and mortars, wooden hand- spikes are used for manoeuvering tliem. Tliose for mortars are shod with iron, which is turned up in a way to prevent slipping on the platform. Guns with iron carriages have iron handspikes, made to fit into tlie mortises of the truck- wheels. Elevating-har is a stout bar of iron with one end squared and made to fit into the ratchets on the breech of the piece for the pui-pose of giving elevation. It is operated as a lever, the fulcrum being the ratchet-posts of the carriage. The implements and machines used for mechanical manoeu- vres., for the inspection., and for the aiming of cannon, are de- scribed under those lieads respectively. MOTION OF PROJECTILES AND DEYIATINa CAUSES. S06. A projectile fired from a cannon is acted on by four distinct forces, viz.: First, the projectile force ; second, the force of gravity ; third, the resistance of the air ; fourth, the friction against the surface of the bore. With tlie exception of gravity, none of these forces are con- stant, varying not only for different pieces, but for different shots from the same piece. The projectile force is that produced by the combustion of the powder in the piece, causing sudden development of gas, the expanding force of which, acting on the projectile, impels it forward and out of the piece. It is physically impossible to ob- tain exact uniformity in the charges. In practice tliere will ahvays be a difference in weight and shape in the cartridges, and in pushing them home, greater pressure will be applied at one time than at anotliei-, thus causing want of uniformity in combustion. The temperature of the piece, arising from pre- vious discharges and from the temperature of tlie air or rays of the sun ; the nature of the projectile and its movement in the bore ; the condition of the bore with respect to humidity and foulness, — all have more or less influence on the combustion of the powder, and consequently on the velocity and range. Above all, however, is the want of uniformity in the quality of powder. In this respect considerable latitude must be allowed in the size and density of grain or pellet, in the manipulation of the ingre- dients, and in its condition resulting from age, moisture, and handling. With small charges, especially with fine-grained MOTION OF PROJECTILES. 57 powder, it is possible to so mix the contents of different barrels for any series of shots as to secure a fair degree of uniformity for that particular occasion ; but with charges requiring large quanti- ties of powder, this, except to a limited degree, is impracticable. The force of gravity. As soon as the projectile leaves the muz- zle of the piece this force has free power to act, and draws the projectile downwards, causing it to describe a curve. The resistance of the air. The projectile, in passing thi-ough the air, meets from it a resistance depending in intensity upon the velocity, the shape of the projectile, and density of the air. This resistance consumes a portion of the projectile force, whicli, being gradually diminished, causes the projectile to pass over unequal spaces in equal intervals of time. These spaces gradually diminish- ing, give to the trajectory unequal curvatures in its two branches, that of the last pai't being much more curved than the first. Atmospheric resistance increases as the square of the velocity, and with the cross-section of the projectile exposed to the action of the resistance. It is manifest that the resistance due to the atmosphere varies with the density of the latter, and this depends upon and varies with the temperature, the humidity, and the barometric press- ure. The retarding effect of rain is evident. The foregoing influences operate principally in a vertical di- rection, and therefore affect only the range. Other influences affect lateral accurac}'^, among which may be mentioned wind., the velocity and force of which are classified as follows : Telocity. Pressure on Common designations of the force 1 square In 1 hour. In 1 sec'd. foot. of the wind. Miles. Feet. Lbs. 1 1.47 0.005 Hardly perceptible. 2 3 2.93 4.40 .020 \ .044 5 Just perceptible. 4 5 5.87 7.33 .079? .123 5 G-entle, pleasant wind. 10 15 14.67 22.00 .492 \ 1.107 5 Pleasant, brisk breeze. 20 25 29.34 36.67 1.9G8> 3.075^ Very brisk. 30 35 44.01 51.34 4.429 \ 6.027 5 High wind. 40 45 58.68 66.01 7.873? 9.963 5 Yery high. 50 73.35 12.300 A stoma or tempest. 60 88.02 17.715 A great storm. 80 117.36 31.490 A hurricane. 100 146.70 49.200 A hurricane that tears up trees. carries buildings before it, &c. 68 MOTION OF PROJECTILES. It is evident from the foregoing' that the effect of wind, on so large a body as a cannon projectile, is considerable. This effect is in direct proportion to tlie strength of the wind and the time of flight of the projectile. When the wind crosses the plane of fire, the deviation of spherical projectiles is on the side towards which the wind is moving ; with elongated projectiles, especially shells and cored shot, the wind has a slight tendency to cause them to go in the opposite direction. Wind coming from the left tends, therefore, to correct the drift of rifle projectiles, the latter being always to the right ; when coming from the right it augments the drift. A front wind diminishes the range; when coming from the rear it increases, but to a very slight degree, the range. When the range is great the projectile may have to traverse several currents of air of different directions and velocities. This would have the effect of giving a waving motion to the pro- jectile. The condition of the atmosphere with reference to mirage has a marked influence upon accuracy of aiming; for it is evident that a projectile will not strike the object if the piece is directed only at the reflected image of it. Aberrations arising from atmospheric influences are so nu- merous and subtle as to make it impracticable to formulate them into tables useful for practical gunnery. Practice at small-arm tiring, as now conducted at rifle-ranges, leads to habits of obser- vation and exercise of sound judgment highly advantageous ta the artillerist. Friction against the hore. The projectile, in passing along the bore, experiences more or less friction ; this has a retarding effect, varying the velocity and consequently the range. The unequal degree of friction at different parts of the bore may cause the projectile to leave the muzzle with a greater pressure on one side than on the other, forcing it to deviate from the true line of fire. This is more particularly the case with spher- ical projectiles, in which there is considerable windage and bal- loting, than with rifle projectiles. Resistance from rifling. The cup or sabot of an elongated projectile, expanding from the pressure of the gas, fills the grooves, which, being inclined to the axis of the bore, offer resistance to the forward motion of the projectile. That side of each groove towards the muzzle is the one against which the expanded sabot constantly impinges, and is called the driving side. Owing to the mechanical impossibility of constructing guns and projectiles of exact uniformity, a certain departure from AIMING. 59 the true dimensions is allowed in receiving- them from tlie manufacturer. This, to a certain degree, prevents uniformity in firino'. Ronohness of tlie bore and projectile, especially with rifles, influences velocity, accuracy, and i-ange. Tlie bore be- comes foul from firing, and this foulness is hard and roui>:h or soft and unctions, depending on the humidity of the atmosphei-e.^ or whether the sponge is moist or dry. Witli rifle projectiles, lubrication, or tlie want of it, has a marked effect upon their range and accuracy. Want of uniformity in the density, weight, figure, and centre of gravity of projectiles, are other sources of error in firing. In many instances these various sources of aberration may combine in such manner as to partly neuti'alize each other. On the other hand, they may so fall together as to produce the maximum degree of inaccuracy. In addition to the foregoing, there are other sources of error in firing, which, although exceeding!}^ minute, nevertheless exist. Among these may be mentioned the influence of the axial rota- tion of the earth; the spring of the carriage; the dip of the muz- zle ; the effect of the rays of the sun in heating one side of the piece more than the opposite side, and a like effect on the pro- jectile. From the foregoing, it must be evident that exact uniformity of firing with any piece is an impossibility. It is b}'' practice alone that the artillerist can be brought to distinguisli between inherent defects and faults of gunnery which lie may correct. Aiming. 20 1". To aim a piece of artillery is to give it such a direction and elevation as will cause the projectile to strike the object^ and the rule is : first give the direction, and then the elevation. With the exception of mortars, all modern pieces are furnished with two sights : a front one and a rear one. These are situated either on the line of metal ^ or slightly to the right of it in a plane parallel to the plane of lire. The front sight is securely attached to the piece by means of a screw, and for the heavier class of guns is over the axis of the trunnions. The rear sight is on the breech, fitting into a socket attached to the piece with screws, and when the gun is to be discharged is removed from the socket. For the 10 and 15 inch guns the breech sight is without grad- uation, and serves merely to give direction to the piece, the ele- 60 AIMING. vation being given by means of the elevating-arc, or, when prac- ticable, with the quadrant applied in the muzzle. 208. For siege and Parrott guns the breech sights are grad- uated to correspond to degrees and parts of degrees of elevation of tlie axis of the bore, and have a slide to move up or down. This slide has a screw thread cut on one end of it, upon wiiich works a nut with four short arms ; through each of these arms is a small hole for sighting. The screw upon the slide is for the purpose of giving lateral motion, when allowing for drift. Each kind of gun has its particular breech sight, but, as there are in service many of old or experimental pattern, they should be veritied for the particular pieces upon which they are to be used. This is done by directing the piece at some well-defined point at a distance of 1000 yards or more, and on the same hori- zontal plane with the axis of the trunnions. A straight-edge and spirit-level applied to the face of a trunnion suflSces for this operation. Place the slide of the breech sight at any degree of the graduation, and, sighting through it at the object, give the piece the corresponding elevation. Insert the gunner's quad- rant into the bore, and ascertain from it the inclination of the axis of the piece. If the reading on the breech sight corre- sponds to that of the quadrant, the former is correct. The line of sight passing through the zero of the breech sight is parallel to the line of fire. 209. For 10 and 15 inch guns an elevating-arc is used. This •consists of a strip of brass attached to the base of the breech parallel to the ratchets. It is graduated into degrees and parts of degrees, and a pointer, attaclied to the ratchet-post, indicates the elevation or depression of the piece. When the pointer is at zero, the axis of the piece is horizontal. Besides the graduation on the arc, the ranges in yards for the ordinary charges for shot and shell are given. In batteries for garrison and sea-coast defense, where the platforms ai-e fixed, the line of metal may be considered as per- manent; but with siege guns, mounted on traveling carriages, the wheels are liable to vary in position from unevenness of ground, or unequal settling in newly -constructed platforms. This line is constantly changing, and approximates the higher wheel in proportion to the difierenceof level between tiie wheels ; hence, to secure accuracy of fire, allow^ance must be made by observing where the shots strike and correcting the aim accord- ingly. Deviation from this cause is always towards the side of the lowest wheel. 210. All range tables are made out with reference to the horizontal plane passing through the axis of the trunnions; AIMING. 61 when the object to be fired at is situated on a plane lower than this, an allowance must be made for this difference of level by deducting from the elevation laid down in the table of ranges. The following table is calculated for cases in which the piece h above the object; it will also serve with sufficient degree of approximation for cases in wliich the piece is below tlie object, by simply reversing the method of application ; ^. e., by adding, instead of subtracting, the quantity due to the height and. dis- tance. Yards. lOCO 1100 1200 1300 1400 1500 1600 1700 1800 1900 2000 2100 2200 2300 2400 2500 3000 3500 4000 4500 5000 HEIGHT. 1 Ft. 2 Ft. 1.1 1. .9 .9 5 4 1.3 1.3 1.2 1.2 1.1 1. 1. 1. .9 .8 .7 .6 .5 .5 4 Ft. 8 Ft. 16 Ft. o / o / / 4.6 9.2 18.3 4.2 8.3 16.7 3.8 7.6 15.3 3.5 7. 14.1 3.3 6.5 13.1 3. 6.1 12.2 2.9 5.7 11.4 2.7 5.4 10.8 2.5 5.1 10.2 2.4 4.8 9.6 2.3 4.6 9.2 2.2 4.3 8.7 2.1 4.2 8.4 2. 4. 7.9 1.9 3.8 7.6 1.8 3.6 7.3 1.5 3. 6.1 1.3 2.6 5.2 1.1 2.3 4.6 1. 2. 4.1 .9 1.8 3.7 Ft. 64 Ft. 36.7 33.3 30.6 28.2 26.2 24.4 22.9 21.6 20.4 19.3 18.3 17.5 16.7 15.9 15.3 14.7 12.2 10.4 9.2 8.1 7.3 13.3 6.7 1.1 56.4 52.4 48.9 45.8 43.1 40.7 38.6 36.7 34.9 33.3 31.9 30.6 29.3 24.4 21. 18.3 16.3 14.7 96 Ft. 50. 40. 31.7 24.6 18.6 13.3 8.7 4.7 1.1 57.9 55. 52.4 50. 47.8 45.8 44. 36.7 31.4 27.5 24.4 22. "When the height of the piece above the water or horizontal plane is known, the angle of depression for different distances can be found thus : Find the angle for any height not given in the table, as follows : divide tlie given height into parts, which are found in the table, using the largest numbers possible ; and add the angles corresponding to those parts, for the required distance. Example : Required the angle for distance 1000 yards and height 130 feet. 130 feet gives the parts 96^ 32% and 2'; the sum of tlie angles for these heights is 1° 50^+ 36.7^+2.3^= 2° 29^; the amount to be deducted from the elevation as given in the table of ranges for the particular piece used. 62 AIMING. 211. Owing to the great range at which rifled guns are used, and of the accuracy of lire demanded of them, it is important that they should be provided with aiming apparatus more per- fect than the coarse and clumsy sights heretofore supposed to be sufficient for artillery purposes. The Lorain sight, {Plate F/,) of which the following is a brief description, combines the properties most desirable in a sight for heavy rifled guns. This instrument is essentially a transit with a vertical and horizontal limb, the former to give the required elevation or depression, and the latter to give proper allowance for drift. The telescope (A) has a top, a front and rear open sight (a a% used to bring the object aimed at within the field of view. The vertical limb (B) is graduated to degrees. The least count of the vernier (6) is six minutes. The tangent screw (C) elevates or depresses the telescope. The horizontal limb (D) has a scale of 20° on each side of the zero, which is graduated to degrees. The standards (E E^ are supported by the horizontal limb. The tangent screw (F) moves the horizontal limb to right or left. The base of the instrument (Gr) has on it the vernier (g) of hori- zontal limb, the least count of which is six minutes. When in use, this instrument sits in a seat (H) which is screwed on to the right trunnion of the gun. This seat is so placed that the plane of its top is parallel to the horizontal plane through the axis of the bore. When the verti- cal limb is at zero, the axis of the telescope will be parallel to the axis of the bore, if the zero of the horizontal limb coincides with the mark (I) on the seat. This mark (I) is on a movable piece (K) attached to seat, and its position is easily determined. The elevations given with this sight and with a quadrant do not agree, the latter being measured from the horizontal and the former from the line from sight to object. In firing from above an object, the telescopic sight requires more elevation than the quadrant. If from below an object, it requires less elevation than the quadrant. When the piece is to be fired, the instrument is lifted out of its seat. One instrument suffices for three or four guns, it being -carried from piece to piece as they are prepared for firing. For short range and rapid firing, the pieces should, in addition, have the ordinary sighting arrangements. Note. — The proper place for the sight is on the left trunnion ; t)ut as, with carriages now constructed, it would be interfered with by the crane, it is placed on the right trunnion. AIMING MORTARS. 63 Aiming mortars » S12. Mortars, like other cannon, are aimed by first giving the direction and then the elevation. The elevation, which is nsuallj'^ that of the greatest range of projectiles in vaciio^ viz., 45°, is determined by applying the quadrant to the face of the piece, and raising or lowering the breech until that number of degrees is indicated. The charge of powder is varied to suit the required range. To give the shell, for the same range, a greater velocity in the descending branch of its trajectory, the mortar is sometimes fired at an angle of 60^, in which case the charge of powder must be increased accordingly. As mortars are usually masked from the object to be bom- barded by an epaulment or parapet, difierent means from those used with guns become necessarj' for giving them their direction. There are several processes employed, all of which, however, are reduced to determining practically two fixed points which shall be in line with the piece and the object, and sufficiently near to be readily distinguished by the person pointing tlie mortar. These points determine a vertical plane whicli, when including the line of metal, becomes the plane of fire. The various methods are I'xplained in pa7's. 342 and 343. 213. The following is a description of Dyer's pointing appa- ratus, and instructions for its use. This method is easy of application, and is especiallj' adapted for use with mortars mounted on centre-pintle carriages; it is also readily adapted for use with mortars mounted on ordinary and temporary platforms. Practically it is independent of the distance from the crest of the parapet to the platform. The method is as follows : Find the point where the vertical plane containing the directrix of the platform cuts the interior crest of the parapet. At this point establish a level plate containing an arc graduated both ways from the point where the vertical plane cuts it, the centre "being the point first established on the interior crest. An arm with two vertical sights revolves about this point as a centre, and determines, by means of an indicator attached to the front of the arm, the angle made by any object with the vertical plane through the centre, called the plane of the zeros. The mortar being given the same angle with the plane of the zeros, the plane of fire will practically intersect the object. To apply this method to a mortar mounted on a centre-pintle •carriage : On the rear of the platform, with the centre of the pintle as a centre, describe an arc. Find the point where the 64 RICOCHET FIRING. plane of the zeros cuts this arc, and mark the point zero. Divide the arc both ways from the point into degrees and parts of de- grees. An indicator attached to the centre of the rear transom (in the vertical plane containing tlie axis of the piece) will always mark the degrees to the right or left of the plane of the zeros. {Plate VII.) Description of the pointing instrument. A horizontal iron plate is permanently established on the par- apet, the rear edge being on the crest and the centre in the plane of the zeros. In order that the same instrument may be used at different places in a work, or be removed when not in use, a detachable plate containing the graduation and sights is adjusted to the permanent plate, as sliown in Fig. 1. P is a pintle on the de- tached plate which fits into a socket in the permanent one. L L are levels on the detached plate J inch below the upper surface of the plate. S S are leveling screws. By the use of this plate the index arm will always be made to move in a horizontal plane. Application of fhe method. 1st. Place the plate containing the graduated arc on its bed^ and level it by means of the tangent screws ; then place the arm, to which the sights are attached, on the plate. Traverse the chassis until the index on the rear transom indicates the required number of degrees as indicated by the instrument. If the arm of the instrument be to the right of the zero, traverse the chassis to the left ; and vice versa. For the successful operation of this method with the centre- pintle mortar carriage, it is essential that the guides of the top- carriage should fit true and snug to the chassis rails. Ricochet Firing. *J14. The angle of fall of projectiles in vacuo is equal to the angle of elevation; but in air the angle of fall is somewhat greater. It is known from experience that a projectile falling upon ground of ordinary firmness, at an angle not greater than ten degrees, or upon water at four or five degrees, will generally make one or more bounds. In this case the projectile is said to ricochet. The purpose to be sought in ricochet firing is to cause the projectile to bound along near the surface of the ground or water^ CARRIAGES. 65 and thus increase the chances of hitting the object to be clestroyecl. It is chiefly advantageous against troops in the field, and against boats and unarmored vessels. With the exception, however, of occasional use against the latter objects, it is generalh'^ but inci- dental to direct firing. Owing to the inequalities dt ground, it is uncertain of effect when employed against objects on land. Spherical projectiles are more certain of ricochet than those of elongated form ; with the latter the first graze usually causes them to tumble, after which their motion is both feeble and erratic. The pieces principally employed for ricochet firing are the 8-inch howitzer and the 8 and 10 inch siege mortars. The first two may be used when the angle of fall is less than ten degrees, and the latter when the angle of fall is less than fifteen degrees. With the howitzer, a range of 2000 yards may be obtained; with the mortars, the limit of ricochet is about 1000 yards. With the 15-inch gun, the most effective ricochet upon smooth water is obtained from two degrees elevation; this, with the piece fifteen feet above the water, will cause the first graze to take place at a distance of about 1500 yards, giving a rebound of about 800 yards in length and 100 feet in height. The next rebound will be about 500 yards in length, after which they rap- idly diminish until towards the last, when the projectile appears to almost roll upon the surface of the water. The extreme range at this elevation is about 4000 yards, and the number of distinct ricochets about thirty-five. The slightest roughness of the water has a decided effect upon ricochet, diminishing both accuracy and range. With elongated projectiles, after the first strike, the course is quite erratic, and they are, therefore, entirely unsuited for accu- rate ricochet firing. CAERIAGES. 5215. Carriages for artillery are classified as traveling and stationary. The former are for artillery that is to be moved from place to place; the latter, for that occupying fixed positions. Strength, durability, and facility in serving the pieces are the chief requisites for all carriages. Stationary carriages consist of two parts : the carriage — or, as it is usually called, the top-carriage — and the chassis, and, with the exception of that for the flank-casemate howitzer, are all constructed of wrought-iron. 216. The top-carriage {Fig. 1, Plate VIII) is composed of two 66 CARRIAGES. cheeks, held together by two plates of boiler iron, called the front and rear transoms. Each cheek is formed of two plates of boiler iron cut to a trianoular shape, separated by interposing at the edges the vertical portion of a T-shaped bar. The hor- izontal branches project over each side to form a double flange, giving stifthess to the cheeks. Flat bars of iron are placed between the plates at suitable intervals to stiffen the cheeks in the direction in which the weight and recoil of the piece bear upon them. All these parts are held together by screw bolts. The piece rests between the cheeks, and is supported on them by the trunnions, which work in circular cavities called trunnion- heds. This permits the piece to have free play for purposes of elevation and depression. For most pieces, the motion of the top-carriage to and from battery is regulated by a pair of truck-wheels, one on each side, which work on an eccentric axle placed underneath and a little in front of the axis of the trunnions. The wheels are thrown into gear by means of handspikes in- serted into sockets upon the ends of the eccentric axle ; the wheels then rest upon the top of the chassis rails, and only the rear part of the soles of the top-carriage rest on the chassis rails and have sliding friction. The wheels are thrown out of gear in the same manner ; the entire soles then have sliding friction upon the chassis rails, thus checking recoil. In the 15-inch gun carriage there are two pairs of truck-wheels, one pah" being placed in front, as just described, and the other pair near the rear end of the carriage; the rear wheels only are on eccentric axles, and wlien these are out of gear the soles of the top-carriage rest fairly on the chassis rails, and the motion is on sliding friction. When the rear wheels are in gear the front wheels also touch the chassis rails, and the top-carriage moves on rolling friction. To prevent the rear wheels from working out of gear while the gun is being run from battery, or jumping in gear when the piece is fired, pawls are provided for locking the rear axle. "When the rear wheels are in gear^ motion is communicated to the carriage by means of a handspike on each end of the front axle. This handspike carries a double pawl, which works in ratchets or cogs on the truck-wheels. The handspike is arranged with a counterpoise, consisting of a heavy piece of iron on the short arm of the lever. In the 10 and 15 inch guns, as also in mortars, the elevation and depression are given by means of a lever, called the elevat- ing-bar. The point of this bar works in ratchets cut in the breech of the piece. The fulcrum — usually called the ratchet- CARRIAGES. 67 post — rests on the rear transom of the ^"un carriage. It is of cast-iron, and has several notches for adjusting the position of tlie elevating-bar. Carriages for the 8-inch rifle (converted) have an improved elevating apparatus. This is described in par. 320. Guns of the Parrott pattern have an elevating screw. This is attached to the rear transom of the carriage at its lower end, while the nut is connected to the cascable of tlie gun. The screw is worked by a handle passing througli it above the nut. Both screw and nut admit of movements by whicli the screw can take any position required in the various degrees of elevation. Slf • Chassis. The chassis is the movable railway on which the top-carriage moves to and from battery. It is composed of two wrought-iron rails inclined three degrees to the horizon, and united b}^ transoms, as in the top-carriage. In addition to the transoms, there are several diagonal braces, to give stitlness to the chassis. {Fig. 1, Plate Vltl.) For the 10-inch gun and all smaller carriages, the chassis rails are single beams of rolled iron, 15 inches deep; for all calibres above, the rails are built up of long rectangular pieces of boiler plate and T-iron, in a manner similar to that of the cheeks of tlie top-carriage. Traverse-wheels. The chassis is supported by wheels, which allow of its having a horizontal motion, for the purpose of giv- ing the piece a proper direction when aiming. Traverse circles. The traverse-wheels roll on circular bars of iron resting on a bed of masonry or wood. Pintle. This is an upright journal, around which the chassis traverses. It is a stout cylinder of wrought-iron, inserted in and firmlj'^ fastened to a block of stone called the pintle Mode. When wooden platforms are used it is fastened as described in par. The centre-pintle carriage is one in which the chassis is attach- ed to the pintle at its middle, and revolves around it through tlie entire circumference of the circle. The traverse circles are con- sequently continuous. By this arrangement a much greater horizontal field of fire is secured. Thii front-pintle carriage is one in which the chassis is attached to the pintle by its front transom ; the traverse circles are seg- ments of circles. The^m^Ze key is a stout key of iron passing through the pintle, to prevent the chassis from jumping oft" when the piece is dis- cliarged. The pintle is surrounded by a plate firmly bolted to the block ; this plate is called the pintle plate., or friction plate. 68 CARRIAGES. Hurters and counter-hurters. These are flat pieces of iron bolt- ed, — the first to the front and the latter to the rear part of th& chassis rails, to check the motion of the top-carriage when the piece is run in battery^ and wlien it recoils upon being fired. In carriages of Improved model the hurters and counter-hurt- ers are stout bufi'ers of gutta-percha, which, absorbing the shock, prevent racking of the carriage. Guides are stout claws of iron bolted to the cheeks of the top- carriage, and, catching under the flanges of the chassis rails, pre- vent the carriage from slipping or jumping otf. Through the chassis, immediately over the pintle, runs an eccentric axle, carrying upon each end a truck-wheel. This axle and wheels are for the purpose of throwing the chassis in gear^ thus raising the pintle transom from the friction plate and allow- ing the carriage to be traversed with freedom. It is prescribed that the chassis shall be out of gear when the piece is fired. This, however, is not necessary, and the omission of it when firing saves much time and labor. The lighter class of carriages are without the arrangement just described. In the improved pattern of carriages the axle and truck-wheels above mentioned are replaced by two stout rollers attached to bolsters on the front end of the chassis. These rollers move upon the friction plate, and give firm support and easy motion to the chassis. Casemate carriages differ from barbette carriages in being much lower, but their mode of construction is essentially the same. The pintle is placed immediately under the throat of the embrasure, and the chassis is connected to it by a bar of iron called the tongue. Recoil checks. For the 10-inch smooth-bore and all below that calibre, recoil is checked simply by the inclination of the chassis rails and the sliding friction thereon of the top-carriage. To increase this friction, the rails should be sanded with sand free from pebbles. 318. Pneumatic buffers or air-cylinders are devices for check- ing recoil through the agency of atmospheric air. At present, only the 15-inch gun is thus provided. Between the front ends of the chassis rails are attached two cast-iron cylinders each 110 inches long, with an interior diame- ter of 14.25 inches. The ends of the cylinders are closed with tight-fitting heads secured with screw bolts. A piston works in each cylinder. The rods of the pistons pass out through the rear cylinder heads and are attached, by nuts, to a heavy transom on the rear end of the top-carriage. The cylinders have the same CARRIAGES. 69 inclination as the chassis rails, and are secured to the latter by three cylinder transoms. Wlien the piece recoils tlie piston-rod is withdrawn, and the air contained in the cylinder compressed between the piston and the rear head of the cylinder, A small hole in the front head admits air to supply the vacuum in front of the piston. The air in rear of the piston thus forms an elastic cushion, offering but slight resistance to the first movement of recoil, but gradually increasing in resisting force as the carriage moves back, until finally the force of recoil is overcome and the top- carriage is brought to a state of rest. The shock of recoil is to a great extent absorbed without sudden strain to the carriage. The top-carriage must be out of gear when the piece is dis- charged ; it then moves on the chassis with sliding friction. This, together with the inclination of the chassis rails, assists in check- ing the recoil. When the carriage is in good running order, it generally runs forward a short distance by the reaction of the compressed air after recoil. To run the piece in battery^ the top-carriage is thrown into gear ; it then moves forward, the air is compressed in front of the pistons, and, escaping gradually through the small holes in the heads of the cylinders, allows the carriage to move forward with a gentle motion. The weight of the air-cylinders with attachments is about 5000 pounds. 51 9. Hydraulic buffer. This is a recoil check, in construction veiy similar to the air-cylinder. A liquid is used instead of air, but the principles of operation are similar. At present these buffers are furnished only with the (convert- ed) 8 -inch rifle, and are described in connection therewith. (See par. 320.) Water or any other free-flowing liquid answers for filling the cylinder. In cold weather a non-freezing liquid, -as a mixture of glycerine and water, methyl and water, or some of the non-freezing oils, must be used. The greatest care must be observed to have in the cylinder the exact amount required. The difficulty of properly regulating all of these matters makes the hydraulic buffer greatly inferior to the air-cylinders. 520. Friction bars. This device for absorbiug recoil is sup- plied only with the experimental 8-inch rifle (converted). It is described \npar. 320. 3^21. Depressing carriages. These are carriages that permit the gun to lire over a parapet in the usual manner, and, upon recoil, allow the piece to descend behind the parapet, where it ican be reloaded in safety. 70 CARRIAGES. Various plans for effecting this have been proposed, but none actually adopted, in the U. S. service. The King carria ft O i k1 1 s Inch. Inch. Inch. Lbs. 6 105 5 3.5 252 21 108 5 3.5 1070 6 48 3.5 2 70 4 48 1 1 12 11 .75 r'nd Kind op Timbek Used. |- Yellow pine. {Fig. 3, Plate X.) This platform is composed of six sleepers and twenty-one deck-planks. It is laid level, and the front and rear deck-planks are connected by eye-bolts to each sleeper. A bed for the plat- form is first prepared by leveling off the ground, and, if not already solid, the earth should be well rammed. This bed should be sunk only so deep as to allow the upper surface of the platform to be slightly above the surrounding ground, for drain- age. The sleepers are laid parallel to the directrix or plane of fire, three on each side of it, at equal distances apart, so that the holes in their ends shall correspond to the holes in the front and rear deck-planks. The front deck-plank is laid first, and the eye-bolts driven to secure it; the remaining planks are driven up against it, and the last secured, like the first, with eye-bolts. At the rear end of each sleeper a securing stake is driven. The earth, on all sides, should be raised nearly as high as the platform, and well rammed, giving it a slight inclination out- wards, to allow the water to run off. It is of the first importance that the upper surface of the plat- form should be level and true. 76 RAIL PLATFORM. Kail Platform for Siege Mortars. {Fig. 4, Plate X.) 338. Dimensions, &c., of the rail platform. Nambs of Pieces. Siege Moktaks. Kind op Timbkb Used. a> o 05 'P- «t-l o d 1 g CO 1 i bo CI pp-np-po ....„„......„., 2 2 14 Inch. 60 108 48 Inch. 11.5 10 3.5 Inch. 8.5 10 3 Lbs. ■Yellow pine. Rails ■. Stakes (securing).... Platform complete. 825 This platform consists of three sleepers and two rails for the shoes of the mortar to rest on. It is very strong, and easily constructed and laid. The rails and sleepers are notched and fitted together as rep- resented in the figure. The distance between the centre lines of the rails is equal to that between the centre lines of the cheeks of the mortar carriage. The pieces are put together at the bat- tery, and the earth is excavated eight inches in depth, and of suitable length and width to receive the platform. The bottom of this excavation is made perfectly level. The directrix being accurately marked by stakes, the platform is placed in position, its centre line coinciding with a cord stretched between the stakes marking the directrix. The earth is filled in as high as tlie upper surface of the sleepers and firmly rammed; stakes are driven in the rear angles formed by the sleepers and the rails, and one at the rear end of each rail. PLATFORMS FOR SEA-COAST MORTARS. 77 Platforms for Sea-goast Mortars. 13-inch mortars. 229. The size of the platform is 15 feet by 15 feet by 2 feet 2 inches. Dimensions of parts. Nances of Pieces. Deck-timbers. Sleepers Bolts Nuts "Wood screws. Iron plates.... Plankiiig d 15 15 56 56 501 2 or 3 15 Inch. 180 180 24 1 3 180. 180 180 Inch. 12 12 1 2 5.16 54 38 12 Inch. 12 12 r'nd 2 r'nd 0.5 0.5 2 Kemarks. The timber for these platforms to be of oak, or heart yellow pine. Note. — The above is the thickness of the iron plates furnished ; but they are entirely too thin, ciirlino^ up with the weight of the mortar. The}^ should be at least 0.75 inch thick. To lay the platform, a pit is dug 2 feet deep and about 18 feet square on the bottom. The earth on the bottom is well rammed and levelled. The two-inch planking is laid level on the rammed earth, perpendicular to the directrix. The cylindrical bolts are put in the sleepers, and the sleepers, with bolt-heads down, are laid compactly on, and perpendicular to the planking and par- allel to tha directrix. As the deck-timbers are laid the bolts pass through the holes in them. These timbers are laid compactly upon the sleepers, perpendicular to the directrix. The nuts are put on the bolts and screwed down. Both the nut and bolt- heads are countersunk. The iron plates are laid parallel to the directrix, and secured firmly with screws to the deck-timbers, covering nine feet in the centre of the platform and leaving three feet on each side uncovered. The earth is then filled in, and rammed compactly around the platform, with a slight inclina- tion outwards, so as to shed water. The platform for the cen- tre-pintle chassis is 17 feet square ; the bottom of the pit must therefore be 20 feet square. 78 PLATFORMS FOR SEA-COAST MORTARS. 10-inch sea-coast mortar. The size of this platform is 12 feet by 12 feet by 1 foot 8 inches. Dimensions oj" parts. Names of Pieces. Deck-timbers Sleepers Bolts Nuts Wood screws. Iron plates... Planking....... Op. 12 12 44 44 204 2 12 Inch. 144 144 18 1 3 144 144 Inch. 12 12 1 2 5.16 48 12 Inch. 9 9 r'nd 2 r'nd 0.5 2 Kemabks. The timber for these platforms to be of oak, or heart yellow pine. To lay the platform, a pit is dug 1 foot 6 inches deep by 15 feet «qnare ; the remainder of the operation is similar to that for the 13-inch mortar. For descriptions of wooden platforms for sea-coast guns, see ^ar. 635. iart ^mnA. SERVICE OF THE PIECE. The service of the piece consists of all the operations required in loading, pointing, and discharging it. General Rules. S30. To avoid repetitions, and to secure easy reference, the following general rules are inserted collectively. The pai*a- graphs referred to belong to some particular piece — generally the siege gun — and illustrate the application of the rule. I. The implements and equipments required for a piece are taken to it by the detachment when going to the exercises, or they may be placed there previous to that time. They are removed, at the conclusion of the exercises, by the same means, and returned to their proper places in the store- house. It is the especial duty of the chief-of-detachment to see that all that appertains to his piece is complete and in good order. II. At the conclusion of the exercises, and previous to leaving ■a. battery, the officer in charge will dress it, giving the pieces, on the same line, a uniform alignment, direction, and depression. Pieces must never he left loaded. III. The detachments are marched to the battery, and the cannoneers posted at their pieces as prescribed in par. 106. IV. When the equipments are distributed, the gunner buckles the strap of his pouch around his waist, wearing the pouch in such position as to interfere as little as possible with his move- ments. The cannoneer who wears it, buckles on the primer-pouch in like manner. The gunner removes the vent-cover, and clears the vent with the priming-wire. Cartridge-pouches are carried suspended from the left shoulder to the right side. {Par. 256.) V. In loading, the gunner closes the vent by applying the second finger of the left hand tightly upon it, and holding it there from the moment the sponge is introduced in the muzzle until the rammer is withdrawn after the projectile is home, {Par. 238.) VI. When, in loading, the sponge or the rammer is found to (79) 80 GENERAL RULES. be home at the fourth motion, then what is prescribed for the sixth will be executed at i\\e fourth. {Par. 239.) VII. In sponging or in ramming, the knee on the side toward which the effort is made is always bent, the other straightened. The weight of the body is added, as much as possible, to the effort exerted by the arms. {Par. 239.) VIII. When the sponge fits so tightly as to be difficult to move in the bore, ]S"os. 1 and 2 may use both hands in inserting and withdrawing it. {Par. 240.) IX. Cartridges are inserted into the bore, bottom foremost and seams to the sides. {Par. 240.) X. All projectiles having fuses are inserted in th.e bore so that the fuse shall be towards the muzzle. {Par. 241.) XI. A primer is prepared for insertion in the vent by holding it between the thumb and forefinger of the left hand; the lan- yard, wound upon its handle, is held in the right hand, the hook hy the thumb and forefinger; the hook is attached by passing it upward through the eye of the primer; the hook and primer, thus attached, are held by the thumb and forefinger of the right hand ; the primer is pushed into the vent by the thumb. After the primer has been inserted in the vent, the cannoneer who fires the piece drops the handle, allowing the lanyard to uncoil as he steps back to the position from which he is to fire ; holds the handle, with the cord slightly stretched, passing be- tween the middle fingers of his right hand, back up, and breaks to his left and rear a full pace with the left foot, the left hand hanging naturally by his side. {Par. 243.) XII. In aiming guns and howitzers, the gunner places the breech sight in its seat or socket, and aims through it ; gives the proper direction by causing the trail to be moved, commanding left or right, tapping, at the same time, on the right side of the breech for the trail to be moved to the left, and on the left side for it to be moved to the right. The cannoneers at the trail will closely observe the motions of the gunner. {Par. 243.) With mortars, the gunner signals, with his hands, the direc- tion in which he wishes the carriage moved. {Par. 347.) When the piece is pointed, the gunner raises both hands as a signal ; the cannoneers moving the piece then unbar and resume th(dr posts. XIII. At the command j^re, the cannoneer who discharges the piece turns his face from it, pulls the lanyard quickly, but steadily, and fires. Immediatelj^ after the discharge he resumes the erect position, rewinds the lanyard upon its handle, returns it to his pouch, and resumes his post. {Par. 244.) XIV. The gunner, after pointing, goes where he can best observe the effect of the shot; after which he resumes his post. {Par. 243.) GENERAL RULES. 81 XY. Ammunition is not used wiien exercising hy the num- bers. {Par, 244.) XVIi At the command cease firing., pieces that are loaded remain so until further orders ; those that are partly loaded — if with the cartridge only — the cartridge is rammed home ; if the projectile has been inserted, it likewise is rammed home. In both cases the priming-wire is left in the vent, as an indication that the piece is loaded. If the piece is not loaded, it is sponged out. All the cannon- eers resume their posts. {Par, 247.) XVII. When ammunition is used, the instructor, before giv- ing the command load., will specify : with blank cartridges — with solid shot — with shell — with case-shot. {Par. 248.) XVIII. To secure piece., the gunner puts on the vent-cover, and No. 2 replaces the tompion in the muzzle. {Par. 249.) XIX. Sponge and rammer staves are permanently marked with a white ring, to show — with the sponge, wlien it is at the bottom of the bore; with the rammer, when the projectile is home. {Par. 253.) • XX. Rifle projectiles are always to be lubricated previous to loading. They are then easily pushed home, and their range and accuracy are increased. {Par. 254.) XXI. After each twentieth discharge (or thereabouts) with a rifled piece, the bore is washed out and sponged dry. XXII. When an implement is taken up for any purpose it is returned to its prescribed place by the person using it, at the completion of the duty, unless otherwise specified. XXIII. Cannoneers and the gunner resume their proper posts after the completion of any duty, unless otherwise especially directed. XXIV. With all pieces having traversing carriages, pinch- bars are used for making delicate adjustments in pointing, and iron wheel-chocks for holding the traverse-wheels securely in position. {Par. 340.) XXV. Gunners, chiefs-of-detachment, and chief s-of-platoon, give or repeat commands only when it is so prescribed. XXVI. The habitual post of the chief-of-detachment is as specified in par. 106. He has, under the instructor, or officer immediately over him, general supervision of all duties perform- ed by liis detachment. During firings he looks after the supply of ammunition, and sees tliat tliose engaged in preparing and serving it to the piece perform their duties properly. XXVII. All ammunition must be prepared for firing at tlie service magazine. Projectiles will be carefully cleaned of all rust, dirt, or protuberances liable to cause them to stick, or injure the bore. 6 82 GENERAL RULES. XXVIII. Ill the service of a batterj'" of several pieces, the pieces are designated Nos. 1, 2, 3, &c., from right to left ; these numbers are independent of the pei^manent numbers assigned to pieces in a worlv. In directing the pieces to be fired, they are always designated by their battery numbers ; as, Number^ one — Fire ; Number two — Fire, &c. When the wind comes from the riofht, the firing should com- mence on the left, and reciprocally. XXIX. Under the fire of the enemy, the men will be direct- ed to cover themselves by the parapet or traverses as much as may be consistent with the execution of tlieir duties. XXX. Previous to proceeding with any exercise with the pieces, and frequently at other times during the exercises, the instructor, assisted by the other officers, will explain to the men the nomenclature of everytliing appertaining thereto ; the appli- cation and use of the various parts, machines, and implements used ; the. names and use of tlie different parts of the work ad- jacent to the piece ; the kinds of ammunition used ; charges of powder ; kinds of fire ; and, generally, all matters that assist in making the men efficient artillerists. XXXI. In time of actual service, in front of an enemy, two or more detachments, for eacli piece, are necessary, and all should be instructed. These detachments will be designated First reliefs Second reliefs &c. ; and in all battery formations, as roll-calls, parades, &c., will fall in together in the order of their numbers from right to left. XXXn. In aiming, first get a clear view of the object, and see that the piece is approximately in the line of fire before look- ing through the sights ; then look over or through the sights, and if the object be not in the line, instantly give the command to move the trail to tlie right or left. Always aim quickly, as the eye will not then become wearied. XXXIII. The prop upon which the sponge and rammer are supported is a low trestle, or simply a block of wood sufficiently high to prevent the sponge taking up dirt from the ground. The rammer is always laid on tlie side nearest the piece. {Par. 233.) XXXIV. To prevent the projectile from starting forward, guns should be given at least five degrees elevation previous to being run into battery, and running into batteiy should be done so as to prevent sudden jar against the hurters. {Par. 242.) XXXV. In case the friction-primer explodes without discharg- ing the piece, care must be taken not to approach the piece too soon — not less than five seconds — as it may only hang fire, and the recoil would injure any one in the way of it. {Par. 252.) XXXVI. Sponges, after the first fire, should always be moist- SERVICE OF SIEGE GUN. 83 €ned. This not only assists in extinguishing anj'- fragments of -cartridge that might remain burning in the bore, but it prevents 4lie residuum of burnt powder from hardening on the surface of the bore. Fresli water is preferable to salt for moistening the sponge. XXXVII. In all exercises for instruction, duties should be performed as nearly as possible as in actual service, and not by pretense only. To do this, in the service of the piece a dummy cartridge should be used, together with actual projectiles. 'J'lie cartridge may be made of canvas or stout gunny-sacking, filled to the proper weight with coal broken to the size of the powder used for the piece. A worm serves for withdrawing the car- tridge. A strong lanyard attached to the fuse-plug will serve to with- draw the projectile. The free end of the lanyard remains out of the muzzle as the projectile is pushed liome. SERVICE OF SIEaE GUN. {Fig. 1, Plate XL) Description of Piece. 331. Gun, cast-iron; muzzle-loading rifle; twist, uniform, one turn in 15 feet. Number^ weights^ and dimensions. Designation. Calibre Length of piece Maximum diameter.. Minimum diameter , Length of bore (calibres) Number of grooves Width of grooves Width of lands Depth of grooves Windage Initial velocity (feet) Charge (cannon powder) Solid shot Shen (unfilled) Weight of piece Preponderance Carriage and limber Piece, carriage, limber, and implements Horses to transport (good roads) " " (inferior roads) No. 26.5 9. 1280 8. 10. Lbs. Inch. 3, 85. 25. 3570 300 3650 7400 4.5 133. 15.6 9. 0.97 0.6 0.075 0.05 84 SERVICE OF SIEGE GUN. The nomenclature of the carriage for the siege gun and siege howitzer is similar to that for light field pieces as laid down in *'Light Artillery Tactics" ; it is therefore omitted in this book^ Ranges in yards. Elevation. Shot. Shell. Time of Flight. 1° 0^ 540 533 1.37 1° 30^ 790 781 2.05 2° 0^ 1017 1005 2.69 2° 30^ 1240 1224 3.32 3° 0^ 1445 1414 3.94 3° 30^ 1639 1593 4.54 4° 1823 1762 5.14 5° 2170 2071 6.3 6° 2485 2354 7.42 70 2780 2610 8.51 8° 3056 2844 9.57 9° 3313 3061 10.6 10° 3556 3265 11.59 The gun, on its platform, admits of 9° 30^ elevation and 10«^ 30^ depression. On level ground it admits of 12° elevation and 10° depression. By digging a trench for the trail to run in, a still greater elevation may be obtained. In works, it is fired from a wooden platform. {Pai\ 223.) In the field, it may be fired without a platform, when the ground is level and firm; or a temporary platform may be extemporized from such beams, planks, or logs as maj^ be at hand. To serve the piece. 332. Eight men are required : one chief-of-detachment, one gunner, and six cannoneers. The implements and equipments are arranged as follows : Three on each side of the piece ; leaning against the parapet, in line with cannoneers. One yard behind, and parallel to the cannoneers of the right ; sup- ported on a prop, heads turned from the epaulment. Handspikes. Sponge.. Kammer } SERVICE OF SIEGE GUN. 85 Pass-box Behind and near iN"©. 4. T» . r^ \ Containini^ friction-primers and lan- irTimer-poucn j- ^^^^, suspended from cascable. ^ , , 1 Containins: priminsr-wire ; suspend- Gunner's poucli | ^^^ f,om cascable^ c- ui I, 1 Containino^ breech siffht: suspended Sig:ht-pouch I f,om cascable. 1^, 1 u 1 \ ^"® ^'^ e.^dh side of piece, near the wneei-cnocKs | ^^^^^ ^1 ^^^^ liurter. Vent-cover Covering the vent. Tompion In the muzzle. T. \ Leaning against the parapet near ^^^0^ / 1^0.2. Tj n , -, 1 Containing cartridges ; at a safe and Kucige-oarrei ^ convenient place near the piece. Sponge-bucket INTear sponge and rammer. Fuse-gauge 1 Fuse-knife | Fuse-wrench }- In filling-room of service magazine. Fuse-reamer I One lanj^ard (extra) J !233. To each two pieces there should be One worm One hammer-wrench One gunner's quadrant.. One vent-punch In filling-room of service magazine. One vent-gimlet. One gunner's level.... One gunner's pincers. When there is no parapet, the handspikes are placed, three on each side, standing between the cheeks and wheels of the car- riage, in front of and resting against the axle-tree. The solid shot are piled on the left of the piece against the par- apet ; the other projectiles are in the filling-room of the service magazine ; the fuses, cartridges, and primers are in the service magazine. To distribute the equipments. 234. The instructor commands : 1. Take equipments. The gunner steps to the cascable ; takes off the vent-cover, handing it to !N'o. 2 to place against the parapet outside of his 86 SERVICE OF SIEGE GUN. post ; gives the primer-pouch to No. 3 ; equips himself with the sight-pouch and his own pouch; clears the vent; levels the piece^ and resumes his post. 'No. 3 equips himself with the primer-pouch. These rules are general for all guns. Nos. 1 and 2, after passing two handspikes each to ]S"os. 3 and 4, take one each, for himself. ISTos. 5 and 6 receive theirs froni ]N"os. 3 and 4. 235. The handspike is held in both hands, diagonally across the bod}^; the hand nearest the parapet grasping it near the small end and at the height of the shoulder, back of the hand down, elbow touching the body; the other hand back up, the arm extended naturally; the butt of the handspike resting on the ground, on the side of the cannoneer farthest from the para- pet, and in line with his toes. 236. When a cannoneer lays down his handspik(^ he places it directly before him, about six inches in front, and parallel to the alignment, the small end toward the parapet; and whenever he thus lays it down for the discliarge of any particular duty, he takes it up after having completed the duty. 23'7. The service of the piece is executed as follows: The piece being in battery, the instructor commands : 1. From battery. The gunner moves two yards to his right. ^NTos. 1, 2, 3, 4, 5 and 6, all facing from the parapet, embar with their handspikes; N'os. 1 and 2 under the front of the wheels; Nos. 3 and 4 through the rear spokes of the wheels, near the felly, under and perpendicular to the cheeks; N"os. 5 and 6 under and perpendicular to the mancBuvering bolts. When all are ready, the gunner gives the command: Heave, which will be repeated as often as may be necessary, and sees that N'os. 5 and 6 guide the trail in prolongation of the directrix • of the embrasure, and as soon as the face of the piece is about one yard from the parapet, commands : Halt, at which all un- bar and resume their posts. If the platform has a slope, N^os. 1 and 2 chock the wheels in front. 1. By the numbers., 2. Load. 23S. N"os. 1, 2, 3, and 4 lay down their handspikes; No. 2 takes out the tompion, and places it near the vent-cover. No. 1 turns to his left, steps over the sponge and rammer; faces to the piece ; takes the sponge with both hands, the backs^ down, the right hand three feet from the sponge-head, the left SERVICE OF SIEGE GUN. 87 liaiicl eio:liteeii inches nearer to it; returns to the piece, entering the staft" in tlie embrasure ; places the left foot in line with tlie face of the piece, lialf-way between it and the wheel ; breaks to the right with the right foot, the lieels on a line parallel to the piece, the left leg straightened, the right knee bent, the body erect upon the hips, and'inserts the sponge-head in the muzzle; the stall" in prolongation of the bore, supported by the riglit hand, the right arm extended, the left hand hanging naturally by the side. ISTo. 2 steps to the muzzle, and occupies a position on the left of the piece corresponding to that of ISTo. 1 on the right. He seizes the staff with the left hand, back down, near to and out- side the hand of !N^o. 1. ]^o. 3 faces about, steps over the rammer, and seizes the staff with both hands, as prescribed for ISTo. 1 with the sponge, and stands ready to exchange staves with ISTo. 1. No. 4, taking the pass-box, goes for a cartridge and projectile ; returns, and places himself, facing the piece, about eighteen inches to the rear and right of ISTo. 2. The gunner places himself near the stock, his left foot ad- vanced; closes the vent with the second finger of the left hand, bending well forward to cover himself by the breech, and with the elevating screw adjusts the piece conveniently for loading. This rule for closing the vent is general for all guns and how- itzers. 239. In the meantime, Nos. 1 and 2 insert the sponge by the following motions, at the commands Two — Three — Four — Five— Six : Two. They insert the sponge as far as the hand of N"o. 1, bodies erect, shoulders square. Three. They slide their hands along the staff and seize it at arm's-length. Four. They force the sponge down as prescribed for two. Five. They repeat three. Six. They push the sponge to the bottom of the bore. ISTo. 1 replaces the left hand on the staff, back up, six inches nearer the muzzle than the right ; N'o. 2 places the right hand, back up, between the hands of N'o. 1, and botli then quickly change their other hands so as to seize the staff with the back of the hand up. If, in executing these motions, or the corresponding ones with the rammer, it be found that the sponge or rammer is at home at the fourth motion, then what is prescribed for the sixth mo- tion will be performed at the fourth. This rule is general. The knee on the side toward which the effort is made is always S8 SERVICE OF SIEGE GUN. bent, the other straightened, and the weight of the body added, as much as possible, to the effort exerted by the arms. This rule is general. 1. Sponge. 340. !N'os. 1 and 2, pressing the sponge firml}^ against the bot- tom of the bore, turn it three times from right to left, and three times from left toriglit; replace the hands by their sides, and withdraw the sponge by the same commands, but by motions contrary to those prescribed for inserting it. When the sponge fits so tightly that it is hard to move in the bore, ISTos. 1 and 2 may use both hands. 2^his rule is general. No. 2 quits the staff, and turning towards IS'o. 4, receives from him the cartridge, which he takes in both hands, and introduces it into the bore, bottom foremost, seams to the side; he then grasps tlie rammer in the way prescribed for the sponge. This rule^ with reference to the bottom and seams of the car- tridge^ is general. No. 1, meanwhile, rising upon both legs, turns towards his left ; passes the sponge above the rammer with the left hand to No. 3, and, receiving tlie i-aramer with his right, presents it as prescribed for tiie sponge, except tliat he rests the rammer-head against tlie right side of the face of the piece. No. 3, as soon as the sponge is withdrawn, passes the rammer under the sponge into the embrasure with the right hand ; re- ceives the sponge from No. 1 with the left; replaces it upon the prop, and resumes his post. No. 4, setting down the projectile and pass-box, takes out the cartridge and hands it to No. 2, the choke to the front ; returns the pass-box to its place, and takes up the projectile. Nos. 1 and 2 force home the cartridge by the same commands and motions as for the sponge. 1. Kajvi. S41. Nos. 1 and 2 slide their hands along the staff to the full extent of their arms ; grasp it firmly ; throw the weight of their bodies upon the staff" and press the cartridge home. No. 2 quits the staff, and turning towards No. 4, receives from him the pro- jectile. No. 1, meanwhile, throws out the rammer, and holds it with both hands, the head against the riglit side of the face of the piece. No. 2, receiving the projectile, introduces it into the bore, base foremost, and reseizes the staff with the left hand. No. 4 re- sumes his post. SERVICE OF SIEGE GUN. 89 l^os. 1 and 2 force home the projectile bj'- the same commands and motions as prescribed for tiie cartridge. At the command ram it is pressed tightly down against tlie cartridge. No. 2 quits the rammer ; sweeps, if necessary, the platform on liis own side; passes the broom to N^o. 1, and resumes his post. N"o. 1 throws out the rammer, and places it on the prop below the sponge ; sweeps, if necessary, liis side of the platform ; returns the broom to N'o. 2, and resumes his post. The gunner pricks, leaving the priming-wire in the vent ; re- sumes his post, and adjusts the breech sight to the distance of the object to be fired at. 1. In battery. 242. N'os. 1 and 2 unchoclc the wheels, (if they have been xjhocked,) and with Nos. 3, 4, 5, and 6, all facing towards the epaulment, embar; IS^os. 1 and 2 through the front spokes of the wheels, near the fellies, under and perpendicular to the cheeks ; Nos. 3 and 4 under the rear of the wheels, and Nos. 5 and 6 under and perpendicular to the stock, near the trail. All being read}'-, the gunner commands : Heave, and the piece is run into battery, Nos. 5 and 6 being careful to guide the muzzle into the middle of the embrasure. As soon as the wheels touch the hurt- er, he commands : Haxt. All unbar, and Nos. 1, 2, 3, and 4 resume their posts. 1. Aim. 243. ISTo. 3 lays down his handspike ; passes the hook of the lanyard through the eye of a primer from below upward, and holds the handle of the lanyard in the right hand, the hook be- tween the thumb and forefinger. This rule for preparing the primer and holding the lanyard is general. Kos. 5 and 6, facing towards the epaulment, embar under and perpendicular to the stock near the manoeuvering bolts. The gunner, placing himself at the stock, as at the command load.1 withdraws the priming-wire ; places the breech sight in its socket; sights through it, and, aided by N"os. 5 and 6, gives the direction, causing the trail to be moved by commanding Left, or Right, tapping, at the same time, on the right side "of the breech for No. 5 to move the trail to the left, or on the left side for No. 6 to move it to the right; and by the elevating screw gives the proper elevation, rectifying, if necessary, the direction. The moment the piece is correctly aimed, he rises on the left leg and gives the command Ready, making a signal with both 90 SERVICE OE SIEGE GUN. * hands, at which ]N"os. 5 and 6 unbar and resume their posts^ The gunner, taking the breech sight, goes to tlie windward to observe the effect of the shot. These rules^ as to the method of aiming^ are general. No. 3 inserts the primer in the vent; drops the handle, allow- ing the lanyard to uncoil as he steps back to his post, holding it slightly stretched with the rigiit hand, the cord passing between the middle fingers, back of the hand up, and breaks to his left and rear a full pace with his left foot, the left hand hangings naturally by his side. These rules for holding the lanyard and breaking off by the cannoneer who fires the piece are general. At the command Eeady, Nos. 1 and 2, laying down their handspikes, take, each, a chock in the hand nearest the epaul- ment, and breaking oflf sideways witli the foot farthest from the epaulment, stand ready to chock the wheels after the recoil. 1. Number one (or the like), 2. Fire. 244. N'o. 3, turning his face from the piece, pulls the lanyard quickly, but steadily, and fires the piece. Immediately after the recoil of the piece, N"os. 1 and 2 chock the wheels and resume the erect position ; No. 3 resumes the erect position, rewinds the lanyard upon its handle, returns it to his pouch, and resumes his post. The gunner having observed the effect of the shot, returns to his post. These rules., as far as they relate to the cannoneer who discharges the piece., and to the gunner., are general. Ammunition is not used when exercising by the numbers. This rule is general. To load without the numbers, 245. The instructor commands : Load. At this command the piece is run from battery, loaded, run into battery, and prepared for firing by the following commands from the gunner: From battery— Load — In battery — Aim — Keady. The instructor commands : 1. Number one (or the like), 2. Fire. At which the piece is discharged. All of these operations are executed as before explained, except that Nos. 1 and 2 sponge and ram without the numbers. SERVICE OF SIEGE GUN. 91. To load and jive continuously. The instructor commands : 1. Commence^ 2. Firing. 246. The gunner gives the same command as in the preced- ing paragraph, with the additional one of Fire, and continues- to load and fire until the instructor commands : 1. Cease. 2. Firing. 24T. The firing then ceases ; pieces that are loaded remain so until f m-ther orders ; those that are partly loaded — if with the cartridge only, have the cartridge rammed home; if Avith the projectile, it likewise is rammed home. In both cases the prim- ing-wire is left in the vent. If the piece has no load in it, it is sponged out; all the cannoneers then resume tiieir posts. If it is intended to discontinue the firing, the instructor directs the chiefs-of- detachment to have the charges withdrawn and the pieces run into battery. These rules are general. Tlie projectile may be withdrawn by depressing tiie muzzle and raising the trail until the muzzle knocks against the ground. Should it not then slide out, allow the piece to stand until (if the atmosphere is moist) the residuum of burnt powder in the bore becomes unctions; then depress the muzzle and raise the trail as before. If the projectile still refuses to slide out, the piece will liave to be discharged; or if it is not desirable to dis- charge it, the charge may be drowned out by pouring water in at the muzzle, afterwards draining it out and pouring a small quantity of fine-grain powder in at the vent and firing it. Cartridges are withdrawn by means of the worm. 248. Before giving the command load^ or commence firing., the instructor, when ammunition is used, will specify : with blank cartridges — with solid shot — witJi shell — or, with case-shot. This rule is general. To change posts. As explained in^ar. 112. To secure piece. The piece being in battery^ the instructor commands : Secure piece. 349. No. 2 replaces the tompion in the muzzle. The gunner puts on the vent-cover, which he receives from ITg. 2, and de- presses the muzzle. This rule is general. 'i)2 ORGANIZATION OF SIEGE GUN BATTERY. To replace equipments. The instructor coraiiiaiuls : Replace equipments. S50. IN'os. 1 and 2 replace the handspikes against the para- pet, those of Nos. 3, 4, 5, and 6 being passed to them by Nos. 3 mid 4. The gunner hangs the pouches on the cascable. To serve the piece with reduced numbers, 351. The smallest number of men with which a siege gun can be served with facility is five — one gunner and four can- noneers. In this case !N"os. 5 and 6 are dispensed with, and the piece is run to and from battery as explained for the siege howitzer. {Pars. 264 and 268.) With four men — one gunner and three cannoneers — N^os. 1, 2, and 3, in running the piece to and from battery, perform duties as before, and the gunner that of No. 4. In loading, No. 2, in addition to his own duties, performs tliose of No. 4. With three men — one gunner and two cannoneers — Nos. 1, 2, -and the gunner perform duties as above. In loading. No. 1 per- forms the duties of No. 3 as well as his own. No. 2 performs those of No. 4, as in tlie preceding case. When No. 2 serves ammunition, he goes for the cartridge, and places the pass-box behind his post before assisting No. 1. to sponge. ^5^. In all firings, when a primer fails, the gunner, after Tvaiting a few moments to see that the piece is not hanging fire, steps in front of the left wheel and, reaching over, pricks; No. 3, reaching over the right wheel, gives him a fresh primer to which he has hooked his lanj^ard. !353. Sponge and rammer staves are marked with a white ring painted around them, to sliow — with the sponge, when it is at the bottom of the bore ; with the rammer, when the pro- jectile is home. This rule is general. 254. Rifle projectiles are always to be lubricated previous to loading; they are then easily pushed home, and their range and accuracy of flight increased. This rule is general. Organization of Siege Gtuns into Batteries for Field Service. 255. It has been found from actual experience that the -4.5-inch siege gun is capable of accompanying an army in the ORGANIZATION OF SIEGE GUN BATTERY. 93 field with almost the same facility as the 12-pouiicler. Its great range, power, and accnracy endow it with many advantages wiien nsed as a liea\y field-piece, and it should form a portion of the artillery of every army organized for campaign purposes. For this service the pieces are organized into batteries of four or six guns each, and equipped after the manner of light field batteries. Each piece is furnished with two caissons of the usual pattern, having, however, only two partitions in each half-chest ; these are parallel to and 4.5 inclies from each side — the outer spaces for projectiles, the inner for cartridges. This arrangement allows 16 rounds for eacli chest, 48 per caisson and 96 per gun. A tray in each chest serves to carry pouches, primers, and fuses. One spare wheel is carried for the caissons of eacli two pieces. Caissons not carrying spare wheels, carry picket- ropes and forage. The picket-rope should be in sections; each section long enough to accommodate tlie horses of one piece and its two caissons, together with a proportional share of spare and other horses. This requires eacli section to be 35 yards long. The ends of tlie ropes should be provided with hooks ; these, besides enabling them to be used more conveniently as picket-ropes, allow of their being used as drag-ropes for extricating carriages from difficult places on the march. Light-artillery harness is used, but, owing to the weight of the pole, breast-liooks of extra strength are provided for the "w heel- horses. The swing team being attached to lead-bars, wheel- traces are required for it. The implements for the piece are as follows : 256. Six handspikes; small ends under sweep-bar, resting on axle, large ends resting on splinter-bar, and secured by a leatlier strap passing from the hounds, through loops on the handspikes, to bucldes on the fork ; or by a rope passed through rings on the handspikes and around through staples on the liounds and fork. One sliori roller ; on the stock between the lunette bolts; secured by a rope passing through a hole in the axis of the roller and fastened to the stock. One trace-rope ; two half-hitches in the middle around the cascable ; ends turned around the manoeuvering bolts, and cross- ing to take up the slack. This secures the piece from sliding on its carriage. Tlie sponge and rammer heads are upon the same staff, which is cut to the shortest practicable length. Two sponges and ram- mers are allowed to each piece, and, together with one worm for each two pieces, are carried upon the sides of the piece, secured ^4 ORGANIZATION OF SIEGE GUN BATTERY. by two stout leather straps buckled around the chase and the body of the gun. The service of the piece, so far as spono-ing and ramming are -concerned, is similar to that for light field-pieces. The sponge-bucket is carried in the same manner as for light field-pieces. One fuse-wrench, one fuse-gauge, one fuse-knife, one fuse-reamer, and one pair of gunner's pincers for each piece are carried in the trays of the limber chests of the caisson. A cartridge-pouch is used instead of pass-box, and is carried by JSTo. 4 suspended from the left shoulder to the right side. Large and heavy horses, particularly for wheel-teams, are selected for the guns. Except where the roads are unusually good, ten are allowed to each piece. Each horse, botli for piece and caissons, is provided with a nose-bag, carried as for a ligiit field battery, and one watering-bucket is allowed for each pair of horses, carried — those for the pieces on hooks attached to the rear axle ; those for caissons as in light artillery. One lifting-jack for each two pieces is carried on one of the caissons belonging to these pieces. The lifting-jack weighs 160 pounds, and is carried on a caisson having no spare wheel. Each caisson is supplied with axes, shovels, picks, paulines, &c., as for a light field battery. Two hundred rounds of ammunition are allowed for each piece ; that not contained in the caissons is carried in transportation- wagons. One spare gun carriage, with limber complete, drawn by six horses, accompanies each battery. Three spare poles for the limber of the piece, ironed and fitted ready for insertion, are cariied on the spare carriage. Each battery is furnished with a battery-wagon and forge. These contain supplies as hereinafter prescribed. The spare carriage, battery-wagon, forge, ammunition, and baggage-wagons form a train, and, on the march, usually accom- pany the light-artillery train. The cannoneers carry their equipments and march by the side of the piece, as in a light field battery. In place of the shoe (which is entirely useless) a stout rope, attached to the ring-bolt of the lock-chain, is substituted. This rope, passed around the felly with tw^o or tliree turns, is held by a cannoneer walking by the side of the piece. In this manner he is enabled to let the wheel go as it approaches the bottom of a descent. ORGANIZATION OF SIEGE GUN BATTERY. 95 Composition of a siege battery of six pieces organized and equipped for campaign service. Captains Lieutenants- Sergeants Corporals Artificers , Trumpeters.. G-uidon Drivers Cannoneers,.. Spare liorses. Total. 9 12 6 2 1 75 78 183 W 6 2 1 150 18 191 C Including first-sergeant, < quartermaster, stable, ( and veterin'y sergeants. j \ 3 blacksmiths, 2 saddlers, \ 1 wheelwright. For 6 pieces, 12 caissons, 1 spare carriage, 1 battery wagon, and 1 forge. 25 1". On dry and firm ground the siege gun may be fired as an ordinary field-piece ; under all other circumstances it requires a platform. When time permits, a good platform may be im- provised from material found in tiie vicinit}^; but to provide against every emergency, a platform for each piece should be carried with the battery, or at least with the train, when easily accessible. The platform is the one described in par. 226. These are carried in transportation-wagons, each wagon carrying three platforms. The supply of projectiles should be about equally divided be- tween solid shot, time, and percussion shells; i. e., one-third solid shot, one-third time-fuse shells, and the remaining third percussion shells. It is unnecessary to have either case-shot or •canister. Each piece is provided with a field-glass and telemeter. 96 ORGANIZATION OF SIEGE GUN BATTERY. 258. The following are the supplies carried in the battery- wagon and forge for a battery of six gnns : Forge A. Contents op Limbeb-chbst, (Smith's tools and stores.) Horseshoes, ISTos. 2 and 3 lbs. Horseshoes, Nos. 2 and 3 lbs. Horseshoe nails, Nos. 2 and 3.. lbs. Washers and nuts, No. 2 Washers and nuts, No. 3 Washers and nuts. No. 4 Nails, No. 1, C lbs. Nails, No. 2, C lbs. Tire-bolts Keys for ammunition chests Linch-washers (caisson) Liinch-pins (caisson) Liinch-jjins (for piece) Chains, Nos. 1 and 2 feet. Cold-shut /S' links. No. 3 Cold-shut /Slinks, No. 5 , Hand cold-chisels Hardie Files, assorted, with handles Buttress , Hand-punches, round and square- Screw-wrench Hand screw-driver , Hand vise Smith's calipers, pair , Dfe^s!pairs:}Nos. 1, 2, 3, and 4 Wood screws, 1 in.. No. 14.. ..gross. Q,uart can of sperm oil Borax lbs. Fire-shovel , Poker , Split broom Hand-hammers Riveting-hammer Nailing-hammer , Sledge-hammer Chisels for hot iron Chisels for cold iron Smith's tongs Fore-punch Creaser Fuller Nail-claw Round-punch Tap- wrench Die-stock Nave-bands, developed Tire-bands, developed +i A No. ■f 05 ^ Lbs. 100 100.00 100 100.00 50 50.00 30 5.25 10 3.20 4 2.15 1 1.00 1 1.00 10 5.00 5 8 1.80 7.30 12 8.37 6 2 1.54 50 2.50 12 2.00 2 2.00 1 0.75 12 10.00 1 1.50 2 2.00 1 2.42 1 0.32 1 1.00 1 0.40 f 4 1.50 1 4 1.83 1 2.10 1 2.70 2 1 3.05 1 1.90 1 1.25 2 6.50 1 1.05 1 1.80 1 10.50 2 3.00 2 3.00 3 15.00 1 1.00 1 1.00 1 2.40 1 5.00 1 2.10 1 3.75 1 6.25 4 11.75 2 2.75 Place. Box A 1. Box A 3. Box A 2, large divis- [ion. 'In box A 2, 91.11 lbs. fin box A 4, 28.52 lbs. {■Inbox A 5, 80.05 lbs. In Box A 5, 80.05 lbs. ORGANIZATION OF SIEGE GUN BATTERY. 97 Forge A. — (continued.) Contents of Limber-chest. (Smith's tools and stores.) Shoeing-tiaranier , Pincers, pair Rasps (12 inches) Shoeing-knif e Toe-knife Pritchel Nail-punch Olinching-pin Oil-stone Leather aprons... Horse-tail brush.. Iron square Padlock Tar-bucket Boxes Tow for packing. Total -(^ A No. .^ ffl 1 ^ 0.82 1 2.00 2 2.15 1 0.33 1 0.30 1 0.85 1 0.80 2 1.00 1 1.60 2 3.00 1 1.00 1 2.00 1 0.50 1 7.00 6 53.45 : 5.00 484.38 Place. -In shoeing-hox, 12.75 lbs. Fastened on inside of the chest-cover with two copper clamps. On the chest. On its hook. One pound of horseshoe nails, No. 3, contains 140 nails; one pound of horseshoe nails, Xo. 2, contains 112 nails; one hun- dred pounds of horseshoes, contain 90 shoes. Contents of forge-body. Tools and Stobes. Square iron, J^ in. and 1 in Flat iron, 11^ in. x 5^, 1 in. x >$, IM in. X 1J$ X M in Round iron, % in Cast-steel, % in. square English blistered-steel Boxes 5 and 6, containing : Horseshoes, Nos. 2 and 3 Horseshoe nails, Nos. 2 and 3 Water-bucket "Watering-bucket (leather) Anyil Vise Bituminous coal Coal-shovel Padlock Tow Total. No. Weig't. Lbs. 100 50 50 10 5 200 20 10 8 100 29 250 5 5 842 Place. In the iron-room. Bars not more than 3 feet long. Square iron in two bun- dles. • In iron-room. On its hook. On the vise. On the fireplace. On stock of forge. • In the coal-box. On coal-box. 98 ORGANIZATION OF SIEGE GUN BATTERY. 1. Anvil-block, carried on the hearth of the forge, and secured by liaving a hole through its axis, through which is passed a lashing-rope. Contents of limber-chesty Battery-wagon C. Tools and Stores. Oarriage-maTcer's tools . Hand-saw Tenon-saw (14 in.) Jack-plane Smoothinff-iJlane Brace, with 24 bits Spokeshave Grange Plane-irons Saw-set Rule (2 feet) G-imlets Compasses, pair Chalk-line Brad-awls Scriber Saw-flies (4% in.) Wood-flies (10 in.) Wood-rasp (10 in.) Trying-square (8 in.) Hand screw-driver Oil-stone Broad-axe Hand-axe Claw-hatchet Claw-hammer Pincers (small), pair Table vise Framing-chisels (1 in. and 2 in.)... Firmer-chisels (54 in. and m in.).. Framing-gouges (1 in. and 1% in.). Augers and handles (H in., ^ in., % in., 1 in., 2 in.) Screw-wrench Felling-axe. Adze Frame-saw Q,uart can of sperm oil. Compass-saw Tacks (carpenters'), M. Measuring-tape Chalk with handles. No. 2 1 1 1 1 1 1 2 1 1 12 1 1 2 1 12 2 1 1 1 1 1 1 1 1 1 1 2 2 2 5 1 1 1 1 1 1 5 1 Libs. 4.00 1.50 4.15 1.80 4.35 0.30 0.30 1.05 0.25 0.14 0.95 0.18 0.10 0.17 0.15 0.87 1.12 0.40 0.60 0.32 1.50 6.00 5.00 .00 .50 .06 .80 .00 1.00 2.60 4.50 2.42 6.00 3.30 4.50 2.70 5.00 2,00 Place. > Fastened to the in- > side of chest cover. -In box O 1,17.20 lbs. 'In box O 2,32.23 lbs. In box C 3, 23.25 lbs. ORGANIZATION OF SIEGE GUN BATTERY. 99 Contents of limber-chest. Battery-wagon C, — (continued.) Tools and Stores. Saddler^s tools and stores. Mallet Clam Hammer Shoe-knives Half -romid knife Shears, pair Sandstones Rule (2 feet) Needles, assorted Collar-needles Thimbles Awls Awl-handles Punches, assorted Pincers, pairs Pliers, pairs.^ Claw-tools Creasers G-auge-knife Scissors, pair Compass, pair Strap-awls Saddler's mallet Saddler's clam Bristles Saddler's thread Bees-wax Black-wax Patent thread Shoe thread lbs- Buckles, assorted (0.75 in. to 1.5 in.) doz... Tacks (iron and copper), assorted. Hand-saws Tenon-saws Blades for frame-saws Total. No. 1 1 1 2 1 1 2 1 100 5 4 36 6 6 3 6 2 1 1 1 1 3 1 1 Lbs. 1.75 5.00 0.65 0.20 0.28 0.47 0.30 0.50 0.75 1.00 6.75 0.75 0.25 1.75 5.00 2.00 2.00 3.00 5.00 5.00 2.00 Place. 1.00 10.00 2..00 ' In box O 4. 173.00 ! 100 ORGANIZATION OF SIEGE GUN BATTERY. Contents of wagon-body. Tools and Stores. Grrindstone, 14-in. x 4 in... Axbor and crank for do... Pintles (for piece) Horse-collars (assorted)... Girths Lead-traces Whips (artillery) Wheel-traces Currycombs Horse-brushes Nose-bags Saddle-blankets , Spurs and straps pairs. Halters and straps , Watering-bridles Bridles (artillery) , Hame-straps Harness-leather sides... Bridle-leather sides.., Sash-cord pieces... Pole-yoke Elevating screw Saw, cross-cut (6 feet) Rope-trace, feet... " Block (treble) for above Block (double) for above Watering-b uckets , c3 " o o d d < No. 1 1 1 10 20 15 5 10 15 15 10 20 5 20 10 6 40 2 3 6 1 1 1 200 fee Lbs. ?60 35 45 12 75 2 48 12 12 11 60 5 65 12 18 8 50 33 10 13 32 12 40 Tools and Stores. Fuse-wrenches Fuse-gauges Fuse-knives Fuse-reamers G-unner's pincers Vent-punches Breech sights Priming-wires (runner's gimlets Primer-pouches Castile-soap Handspikes Tallow Staves — sponge and ram- mer (lashed to body of wagon outside) *Neat's-foot oil gal *Grease, wheel (1-ib cans) Nails, (4, 6, 8, and 10-pen- ny) Claw-hatchet Spirit-level (carpenter's).. Sperm or wax candles.... Rammer-heads Sponge-heads Sponges Sponge-covers Lanyards for friction- primers Dark lanterns Common lanterns Total. No. hD Lbs. 10 36 30 11 50 70 20 2 3 4.60 1100 *In Boxes. The battery- wa.^on here mentioned is that furnished from the arsenals; but, bein^ cumbersome and quite misultable for field service, it is better to utilize its body and limber-cliest by plac- ing them on the running gear of the army transportation-wagon. The limber-chest can be attached to the front part of the wagon- bod}^ by strong iron brackets, and serves as a seat for the diiver. A similar chest can be placed, in like manner, on the rear end in place of the forage-rack. In the front cliest is carried tlie carriage-maker's outfit, and in the rear one that of the saddler. On the middle of each side of the body may be attached a ORGANIZATION OF SIEGE GUN BATTERY. 101 «mall chest for horse medicines, or su^h •.other «?mall ftrijloles as may be required of easy access. When the wagon is thus arranged it is, as f9,^i,ly,d)NT.w^i hyfour liorses as the other by six, and one djriyejr, r^sjK^^dooJbltilii'^s, 's sufficient. ' ' • . v . ->,.'> The arrangement for attaching the draught-horses to siege- gun carriages being similar to that for the army transportation- wngon, the harness used witli the latter will answer for the for- mer. A driver is required for each pair of horses, as in light field -artillery. The officers, first-sergeant, and chiefs -of -detachment are mounted and equipped as for light artillery. When in the presence of the enemy, the ammunition-wagons are kept out of range of his fire, but always near enough to be easily reached by the caissons for replenishing ammunition 'Chests. The battery should be repainted once a year, usually in the spring. To do this, a battery complete, of six pieces, requires : 120 lbs. olive paint; 15 lbs. black paint; 10 galls, linseed oil; 3 galls, spirits turpentine; 12 paint brushes (assorted). Harness, when exposed constantly to the weather, should be •oiled once in four months, requiring each time 6 gallons neat's- foot oil and 30 lbs. tallow. The tallow is melted and mixed with the oil. The harness should be well soaked and washed, and the mixture applied warm and thoroughly rubbed in while the leather is still damp. 259. The following list contains a fair supply of horse medi- -cines for a battery of six pieces : -Assafetida .~. 2 pounds. Aloes 2 pounds. Adhesive plaster 1 yard. Aqua ammonia 1 quart. Alum 1 pound. IBluestone 1 pound. Borax «.. 1 pound. British oil 12 bottles. Blister liquid % quart. •Calomel % pound. Condition powders 2 pounds. Cerate, simple 2 pounds, •G-lauber salts 10 pounds. Flax-seed, ground 8 pounds. Laudanum 1 quart. Xard 5 pounds. Xiunar caustic % ounce. Mercurial ointment ~.. 1 pound. Mustang liniment 6 bottles. Nitre l pound. Olive oil 2 quarts. Opodeldoc 6 bottles. Rosin 1 pound. Spirits turpentine 2 quarts. Spirits nitre 1 quart. Flour of sulphur ^ pound. Sugar of lead 2 pounds. Tartar emetic U pound. Tar 1 quart. Whisky 2 gallons. Farrier's needles 4 Farrier's scissors 1 Horse-fleam 1 Lancet 1 Syringe 1 These should be put up, as far as practicable, in metallic cans :and in strong bottles. When the battery-wagon is arranged as 102 SIEGE HOWITZER — SERVICE. before described, a I^'ey^ will be packed and carried in the boxes- attached to th'i side^ 4>f cthe, body ; otherwise they will be carried ill boxes inside of the body. . . 0,TTA;^TilvMA$TER'S STORES. 260. In addition to the wagons, horses, harness, &c., here- tofore mentioned, there will be required for the battery the fol- lowing : 3 wall tents. 3 wall-tent flies. 3 sets wall-tent poles and pins. 75 shelter tents (double). 10 camp-kettles. 10 mess-pans. 2 trumpets, cords and tassels. 1 company clothing-book. 1 company order-book. 1 company descriptive-book. 1 company morning report-book. These articles, excepting the trumpets, are carried in a trans- portation-wagon ; the same wagon will, in addition, carry two- days' full rations for the men of the battery. The forage is carried in transportation-wagons. Service of Siege Howitzer. {Plate 12.) Description of Piece. , 261. Howitzer, cast-iron; smooth-bore; muzzle-loader. Number^ weights^ and dimensions. Designation". Calibre Weight Length Diameter (maximum) Diameter (minimum) Length of bore (calibres.) Windage Charge (cannon powder) Shell (empty) Preponderance Weight of piece, carriage, limber, and imple'ts.. Horses to transport No. 5.81 Lbs. 2600. 4. 45. 580;. 6660. Inch. 60. 17.5 15. '6'Xi SIEGE HOWITZER — SERVICE. 103 Ranges in yards. Elevatiox. Degrees. 1 2 3 4 5 12.5 15 Shell. Range. Lbs. Yds. 45 435 45 618 45 720 45 992 45 1150 45 2280 45 2300 Time of Flight. Seconds. 1.33 2. 3. 4. 5. Bursting charge of shell, 1 lb. ; charge to blow out fuse-plug, 4 oz. The howitzer on its platform admits of 13 degrees elevation and 10 degrees depression. In works, it is fired from a wooden platform ; or when the ground is level and firm, it may be fired without. It is used chiefly in field works for flank defense. To serve the piece. 262. Six men are required : one chief-of-detachment, one gunner, and four cannoneers. The implements and equipments are arranged as follows : Two on each side of piece ; leaning against parapet, in line with can- noneers. One yard behind, and parallel to Handspikes } Sponge.. Rammer the cannoneers of the right ; sup- ported on a prop, head towards the parapet. Cartridge-pouch Suspended from cascable. Primpr nonoh I Containing f riction.primers and lan- rrmier-poucn | ^^^,^ . g^gpen^j^^j f^om cascable. 6-"-'« PO-h } ^TalZ^caST""' "^'''"'■ Sigl^t-pouoh I'^Cmtfcabr' ''"''• ""'""'"' Wheel-chocks. } One on each side of the the end of the hurter. piece, near 104 rflEGE HOWITZEll — SERVICE. Vent-cover Covering the vent. Tompion , In the muzzle. T, 1 Leanino' a^^ainst the parapet, near tj , , , ■) Containing cartridges ; at a safe and Uuage-Darrei j- convenient place near the piece. Pair of sleeves "] Shell-hooks I In a basket or on a shelf, against the Plummet [ parapet, near Ko. 2. Splints J Sponge-bucket Kear sponge and rammer. Grummet-wad On end of hurter, near No. 2. Fuse-gauge Fuse-knife Fuse-wrench - In filling-room of service magazine. Fuse-reamer | One lanyard (extra) J To each two pieces there should be One worm One hammer-wrench... One gunner's quadrant One vent-punch One vent-gimlet One gunner's level One gunner's pincers... If the piece is without elevating screw, a wooden quoin is nec- essary, and this is under the breech. For the purpose of instruction, a cartridge-bag filled with saw- dust, and a priming-wire bent into a hook, for withdrawing it, are provided, and are in tlie basket. When there is no parapet the handspikes are placed, three on each side, standing between the cheeks and wheels of the car- riage, in front of and resting against the axle-tree. The projectiles are in the filling-room of the service magazine ; the fuses, cartridges, and primers are in the service magazine. To distribute the equipments, ^63. The instructor commands : 1. Take equipments. The gunner steps to the breech; takes off the vent-covet, handing it to No. 2 to place against the parapet, outside of hia - In filling-room of service magazine. SIEGE HOWITZER — SERVICE. 105 post; gives the priraer-poiich to l^o. 3, and the cartridge-poiicli to ]^o. 4; equips himself with tlie sight- pouch and his own pouch ; clears the vent, levels the piece, and resumes his post. No. 3 equips iiimself with the primer-pouch. No. 4, after equipping himself with the cartridge-pouch, assists No. 2 to put on the sleeves. Nos. 1 and 2, after passing a handspike eacli to Nos. 3 and 4, take one each, for himself. The handspikes are held and laid <3own as prescribed in pars. 235 and 236. The gunner directs No. 3 to embar under and raise the breech to enable him to level the piece ; applies his level to ascertain the highest point of metal at the base, which he marks with chalk. In case there is no sight upon the muzzle, he does the same at the latter place, and snaps a chalk-line between to mark the line of metal. !264. The service of the piece is executed as foUovvs : The piece being in battery, the instructor commands : 1. From battery. The gunner moves two yards to his right; Nos. 1, 2, 3, and 4, ^11 facing from the epaiilment, embar; Nos. 1 and 2 through the rear spokes of the wiieels, near the felly, under and perpendicu- lar to the cheeks ; Nos. 3 and 4 under and perpendicular to the manoeuvering bolts. All being ready, the gunner commands : Heave, which is repeated as often as may be necessary. He «ees that Nos. 3 and 4 guide the trail in prolongation of the direc- trix of the embrasure, and as soon as the wheels are about one yard from the parapet commands: Halt. If the platform has an inclination, Nos. 1 and 2 chock the wheels in front. All re- sume their posts. 1. By the numbers., 2. Load. 265. Nos. 1, 2, and 4 lay down their handspikes ; No. 2 takes out the tompion and places it near the vent-cover, and resumes his post ; No. 1 faces to his right, and seizes the sponge-staft' at its middle with the right hand, back up ; places himself at the muz- zle, forces the sponge to the bottom of the bore, and grasps the staff with both hands, the back of the right up and that of the left down. No. 3, facing towards the parapet, embars under the breech or knob of the cascable, and assists the gunner in adjusting the piece conveniently for loading. No. 4 goes for a cartridge and shell ; puts the cartridge in his pouch; takes the shell in both hands; returns and places it on the grummet-wad, and stands, facing the piece, about eighteen inches to the rear and left of No. 2. 106 SIEGE HOWITZER SERVICE. The gunner places himself near the stock, as in ^ar. 238, and closes the vent; adjusts the piece to about one degree elevation, and makes a signal for ISTo. 3 to unbar. 1. Sponge. 366. No. 1, pressing the sponge firmly against the bottom of the bore, turns it three times from right to left, and three times from left to right ; draws it out, turns the sponge-head over to- wards the front, and places the rammer-head against the right side of the face of the piece, holding the staff in both hands, the back of the right down and that of the left up; as soon as the cartridge is inserted, he enters the rammer and pushes the car- tridge home. No. 4 gives the cartridge to No. 2, who, having placed him- self between the wheel and piece, inserts it into the muzzle. As soon as No. 4 has given the cartridge to No. 2, he takes tlie shell-hooks and engages them in the ears of the shell in readi- ness for No. 2, who, making a face and a half to his left, takes hold of the shell-hooks, raises the sliell and, making a face and a half to his right, stands in readiness to insert it into the boi-e, as soon as No. 1 has pushed home the cartridge. 1. Kam. S6'^. No. 1 sets the cartridge home by pressing firmly upon it; throws out the rammer, replaces it on the prop, and re- sumes liis post. No. 2 introduces tlie shell into the bore, keeping the arms of the shell-hook in a vertical plane, and sets the shell carefully against the cartridge, taking care that the fuse is in the axis of the piece. Canister is shoved home by hand. Double charges of canister may be fired. If the piece is to be fired horizontally, or at an angle of de- pression, No. 4 hands a splint to No. 2, who presses it under the shell ; replaces the tongs and, if necessary, sweeps his side of the platform ; passes the broom to No. 1, and resumes his post. No. 1 sweeps his side of the platform, passes the broom back to No. 2, and resumes his post. No. 4, after passing the shell to No. 2, resumes his post. Tlie gunner pricks, leaves the priming-wire in the vent, and", resuming his post, adjusts the breech sight to the distance. 1. In battery. 26§. Nos. 1 and 2 unchock the wlieels, and Nos. 3 and 4,. all facing towards rhe epauhnent, embar ; Nos. 1 and 2 through the front spokes of the wheels, near tlie felly, under and perpen- SIEGE HOWITZER — SERVICE. 107 dicular to the cheeks ; I^os. 3 and 4 niider and perpendicular to the stock, guidhig the muzzle of the piece into tlie middle of the embrasure. The gunner commands: Heave, and, as soon as the wheels touch the iiurter, Halt, when all unbar and resume their posts. 1. Aim. 269. 'No. 3 lays down his handspike and prepares a primer. Nos. 1 and 4, facing towards the parapet, embar under and perpendicular to the stock, near the manceuvering bolts ; N"o. 2, facing in the same direction, embars under the breech or knob of the cascable. The gunner, placing himself at the stock, as at the command load^ withdraws tiie priming-wire, places the centre point of the breech sight accurately upon the chalk-mark on the breech, and, sighting through it, gives the direction. Nos. 1 and 4 move the trail to the left or right at the command Left or Right from the gunner. The moment the piece is correctly aimed, the gunner rises,, and commands : Ready, making a signal with both hands, at which IN^os. 1, 2, and 4 unbar and resume their posts. The gunner, taking with him the breech sight, goes to a good place to observe the effect of the shot. At the command Ready, No. 3 inserts the primer in the vent ; Nos. 1 and 2, laying down their handspikes, take each a chock in the hand nearest the parapet, and, breaking off with the foot farthest from the parapet, stand ready to chock the wheel after the recoil. Tiie breech sight at present used with the howitzer is one of obsolete pattern. When sights similar to those used for siege guns are supplied^ the method of aiming will be the same as for the gun. When the piece is masked, by an epaulment, from the object, the direction is given as explained for mortars. {Par. 343.) 1. Number one (or the like), 2. Fire. fiKO, Executed as in par. 244. To load without the numbers, and to Jire. S*^!. Executed as \npar. 245. To unload. 272. The piece having been run from battery, the instructor directs No. 2 to take out the shell and cartridge, No. 4 carrying- them to their place in rear of the piece ; No. 3, v/ith his hand- spike, raises the breech until the shell rolls to the muzzle, where- it is caught by No. 2, who hands it to No. 4. 108 10-INCH GUN — SERVICE. To load and fire continuously, 273. Executed as in par. 246. To cease firing, 3T4. Executed as mpar. 247. To secure piece and to replace equipments. Executed as in pars. 249 and 250. The howitzer is prepared for campaign service as explained for the siege gun, with such modifications as readily suggest themselves. 275. For transportation, the shells are carried uncharged. To charge them, two men and the following implements, in ad- dition, are required, viz.: One set of powder-measures^ one fun- nel^ one fuse-mallet^ one fuse-setter, one rasp., two grummet-wads, two wipers, one bridge-barrel, together with a supply of fuse- plugs and tow. The fuse-plugs are of wood, and the tow is to stop the fuse- holes until the shells are to be taken to the piece. The shells should be well cleansed on the outside from rust and dirt. This is done at the filling-room of the service magazine. Note. — The shells for the howitzer should be strapped to sa- bots, in which case the loading would be greatly facilitated. The foregoing exercise is for ammunition as now furnished. For the service of the siege howitzer, when used as a mortar, see par. 45S. Service of a 10-inch Smooth-bore G-tjn in barbette. {Fig. 1, Plate 8.) Description of Piece. ^'^6, Gun, cast-iron ; muzzle-loader. Number, weights, and dimensions. Dbsigxation. No. Lbs. Inch. Calibre — ~^ Length of piece Maximum diameter Minimum diameter Length of bore (calibres) Windage Initial velocity (feet) Charge (cannon powder) Solid shot Shell (unfilled) "Weight of piece Preponderance 10.5 1275! 10. 136.6 32. 16.2 0.13 25 128 102 15,000 10-INCH GUN — SERVICE. 109 Carriage, wrought - iron ; front pintle, without air-cj^linders or other recoil checks. The new-pattern carriage will be pro- vided with pneumatic buffers. The top -carriage will weigh*^ 2500 pounds, and the chassis 3500 pounds. Ranges in yards. Elevation. Shot. Shell. Time. Charge. Seconds. 1° 00^^ 511 504 1.33 cc 1° 30^^ 724 708 1.95 ^3 2° 00^^ 916 886 2.56 2° 30^^ 1090 1048 3.15 ft 3° 00^^ 1251 1195 7.71 3° 30^^ 1401 1330 4.25 .- -n 40 00^^ 1539 1455 4.79 2 50 00^^ 1793 1680 5.83 "^ '^ 6° 00^^ 2019 1879 6.82 ^ 70 00^^ 2255 2057 7.78 8° 00^-' 2414 2217 8.71 9° 00'^ 2587 2363 9.60 ;:: 10° 00^^ 2749 2498 10.46 a, 15° 00^^ 3429 »o 20° 00^^ 3976 ...... T— Truck handspikes (iron). Elevating-bar (iron) Sponge... Kammer } The piece admits of 30 degrees elevation and 6 degrees depres- sion. Its platform is a permanent portion of the fortification. To serve the piece. ^KK, Eight men are necessary : one chief-of-detachment, one gunner, and six cannoneers. The implements and equipments are arranged as follows : Two on each side of the carriage^ on hooks. Laid on the carriajre over the rear notches, and perpendicular to the piece ; handle to the left. One yard behind the cannoneers ot the right ; supported upon a prop, the sponge and rammer -heads^ turned from the pai'apet and in- clined slightly from the piece. Pass-box One yard in rear of No. 4. 110 10-INCH GUN — SERVICE. } } Containing f nction-primers and lan- Primer-pouch [• 5'ard; suspended from ratchet- post. Containing breech sight and prim- Ounner's pouch y ing-wire ; suspended from ratchet- post. Chocks (iron) One on eacii hurter. Vent-cover.... Covering vent. Tompion In the muzzle. Shell-hooks Behind and near 'No. 5. Sponge-hucket IS'oar sponge. ■r. ^ r^ 1 \ Containing cartridges; at a safe and Jiua^e-oarrei | convenient place near the piece. When several pieces are served together, there will be one quadrant^ one worm^ one ladle^ one hammer-wrench^ two vent- punches^ one gunner'' s pincers^ two lanyards (extra), and two vent-gimlets to each battery of not exceeding six pieces. Tliese, together with the primers and fuses, are kept in the fillhig-room of the service magazine, where the sliells are prepared for firing and brought to the piece as required. The powder is kept in the service magazine. The shells are strapped to sabots. The fuse-plug is of metal, and at the time of inserting the shell into the piece the paper or lead cap is pulled from the top of the wnter-cap. The solid shot are kept piled convenient to the piece. All the projectiles should be carefully cleansed of dirt, lumps of rust, or other protuber- ances before inserting in the gun. Stands of grape are also provided for occasional use, and are kept convenient to the piece. To distribute the equipments, 3f S. The instructor commands : 1. Take equipments. The gunner mounts upon the chassis; takes off the vent- cover, hands it to No. 2 to place against the parapet in rear of his post ; gives the primiM-pouch to No. 3, equips himself with his own pouch, and clears the vent. No. 4 mounts upon the chassis, takes the elevating-bar, and, under the direction of the gunner, adjusts the piece conveniently for loading and resumes his post, taking with him the bar, which he lays on the ground in rear of him, perpendicular to the piece. No. 3 equips himself with the primer-pouch. The handspikes, when not in use, re- :main on the hooks. 10-INCH GUN — SERVICE. Ill The instructor causes the service to be executed by the follow- ing commands : 1. From battery. 3^79. The gunner places himself two paces in rear of the chassis and commands : In-Gear. l!^os. 3 and 4 take hand- spilves from the hooks, embar in the eccentric sockets of the top- carriage, and, assisted by Nos. 5 and 6, throw the wheels in gear at the command Heave by the gunner. The gunner then com- mands : Embar. ]N"os. 3 and 4 withdraw their handspikes and insert them in the rear and uppermost mortises of the truck- wheels; Nos. 5 and 6 seize the handspikes with both hands above the hands of ^os. 3 and 4, all breaking to the rear with the foot nearest the carriage. The gunner then commands: Heave. ^os. 3, 4, 5, and 6, acting together, bear down upon the hand- spikes and move the carriage to the rear; Nos. 1 and 2 follow up with the chocks. The gunner commands: Embar. ISTos. 5 and 6 let go the handspikes; Nos. 3 and 4 withdraw them, and embar as before. The gnnner commands : Heave, which will be executed as before. The commands embar and heave will be repeated by the gnnner until the face of the piece is about one yard from the parapet, when the gunner commands : 1. Halt, 2. OUT-OF-GEAR. Nos. 1 and 2 chock the wheels ; Nos. 3 and 4 withdraw their handspikes, insert them in the eccentric sockets, and at the command Heave by the gunner throw the wheels out of gear, leaving the handspikes in the sockets. All resume their posts. 1. By the numbers, 2. Load. 280. No. 2 takes out the tompion, and places it b}'' the para- pet in rear of his post. The gunner mounts upon the chassis and closes the vent. No. 1 turns to his left, steps over the sponge and rammer, faces the piece, takes the sponge-stafF with both hands, backs down, the right hand three feet from the sponge-head, the left hand eighteen inches from it; returns to the piece, raising the sponge-staff over the crest of the parapet ; places the left foot on the rail of the chassis, and the right foot upon the parapet, or upon a step placed for the purpose against it ; inserts the sponge- head into the muzzle, the staff in prolongation of the bore, sup- ported by the right hand, the right arm extended, the left hand hanging naturally by his side. No. 2 takes a position on the left of the piece corresponding to that of No. 1 on the right, and seizes the staff with the left hand, back down, near to and outside the hand of No. 1. No. 3 faces to his rear, steps over the rammer, and, facing 112 10-INCH GUN — SERVICE. about, seizes the statF with both hands, as prescribed for No. 1 with the sponge; he then stands ready to exchange staves with No. 1. No. 4, taking the pass-box, goes for a cartridge ; returns ancJ places himself, facing the piece, to the right and rear of No. 2. No. 6, taking a handspike, goes for the shell, followed by No. 5 with the siiell-hooks; No. 5 attaches the shell-hooks to the projectile, and No. 6 passes the handspike through the ring, or, if the sliell is provided with a rope handle, through the loop of the handle; both seize the handspike. No. 5 in front, and, bring- ing the shell up on the left of the piece, place themselves parallel to the parapet, No. 5 behind and near No. 2. In the meanwhile, Nos. 1 and 2 insert the sponge in the bore by the following motions, at the commands two — three— four — five — six : Two. They insert the sponge as far as the hand of No. 1,. bodies erect, shoulders square. Three. They slide their hands along the staff and seize it at arm's-length. Four. Ttiey force the sponge down as prescribed for two. Five. They repeat what is prescribed for three. Six. They push the sponge to the bottom of the bore. No. 1 replaces the left hand on the staff, back up, six inches nearer the muzzle than the right; No. 2 places the right hand, back up^ between the hands of No. 1; both numbers then change the other hand so as to seize the staff back up. ]. Sponge. 281. Nos. 1 and 2, pressing the sponge firmly against the bottom of the bore, turn it three times from right to left, and three times from left to right; drop the hands farthest from tlie parapet by their sides, and withdraw the sponge by similar commands, but by motions contrary to those prescribed for in- serting it. No. 2 quits the staff, and, turning to No. 4, receives from him the cartridge, which he introduces into the bore ; he then grasps the rammer in the way presci-ibed for the sponge. In the meanwhile. No. 1, turning to his left, passes the sponge above the rammer to No. 3, and, receiving the rammer from No. 3, presents it as prescribed for the sponge, except that, re- taining hold with his left hand, he rests the rammer-head against the right side of the face of the piece. No. 3, as soon as the sponge is withdrawn, passes the rammer in front of No. 1 onto the parapet, receives the sponge from No. 1, repl'ices it upon the prop, and resumes his post. No. 4 takes the cartridge from the pass-box and hands it to 10-INCH GUN — SERVICE. 113 No. 2, the choke to the front ; returns the pass-box to its place, and resumes his post. I^os. 1 and 2 force tlie cartridge home by the same commands and motions as in sponging. 1. Kam. 282. Nos. 1 and 2 slide their hands along the staff to the full extent of their arms, and, grasping it firmly, throw the weight of their bodies upon the staff to force the cartridge tightly home ; No. 2 then quits the rammer, which jN"o. 1 throws out and lays upon the parapet. In the meantime, Nos. 5 and 6, carrying the shell as before prescribed, step between tlie parapet and the face of the piece ; No. 6 gives his end of the handspike to No. 2 ; No. 5 gives his end to No. 1, and then places himself on the platform in front of the shell ; Nos. 1 and 2 raise the shell until it is opposite the muzzle; No. 5, applying his hands under it, raises the sabot and inserts it into the muzzle; No. 5 then resumes his post; No. 2 withdraws the handspike and passes it to No. 6, who replaces it on the hooks and resumes his post ; No. 2 passes the shell-hooks to No. 5, who replaces them. Nos. 1 and 2, taking up the rammer, apply its head and force the shell down by commands and motions similar to those pre- scribed for the cartridge; at the command Ram it is pressed tightly down against the cartridge; No. 2 quits the rammer and resumes his post ; No. 1 throws out the rammer, replaces it on the prop, and resumes his post. As soon as No. 4 has delivered the cartridge, he mounts upon the chassis, embars through the ratchet-post with the elevating- bar, and, when the projectile is home, gives the piece an eleva- tion of about 5 degrees, — this for the purpose of preventing the displacement of the projectile when the piece is run into battery; No. 4 replaces the elevating-bar and resumes his post ; the gun- ner pricks, leaving the priming-wire in the vent. 1. In battery. 2§3. The gunner commands: In-Gear. Nos. 1 and 2 un- chock the wheels and place the chocks on the hurters; Nos. 3 and 4 seize the handspike and, at the command Heave by the gunner, bear down slowly until the piece is in motion, regulat- ing it by alternately throwing the wheels in and out of gear, or partially so. As soon as the carriage strikes the hurters, the gunner commands : 1. Out-of-gear, 2. Heave. Nos. 3 and 4 throvr the wheels out of gear, withdraw their handspikes, re- place them on the hooks, and resume their posts. If the car- riage does not move when in gear, the gunner directs No. 3 to o 114 10-INCH GUN — SERVICE. slightly engage a handspike in a rear mortise of the truck-wheel and gently urge the carriage forward. Care must be exercised in this operation that the handspike does not fly forward with violence. As soon as the carriage strikes the hurters, N"os. 1 and 2 lock the wheels with the toggles. 1. Aim. 284. The gunner commands: 1. Chassis in-gear, 2. Heave. At the first command, Nos. 3 and 4 embar in the sockets of the eccentrics, and at the second command, assisted by N'os. 1 and 2, throw the chassis-wheels in gear, and, leaving the handspikes in the sockets, resume their posts ; N"os. 5 and 6 embar in the traverse-wlieels. The gunner withdraws the prim- ing-wire, places the breech sight in the socket, and, sighting through it, gives the direction ; Nos. 5 and 6 move tlie trail to the left or right at the command left or right from the gunner. When the direction has been given, the gunner commands ; 1. Chassis OUT-OF-GEAR, 2. Heave. At the first command, N'os. 1 and 2 seize the handspikes, and at the second throw the wheels out of gear, return the handspilves to their hooks, and resume their posts. Nos. 5 and 6 unbar, return their liand- spikes to the hooks, and resume their posts. No. 3 passes the hook of the lanyard through the eye of a primer, holds the handle of the lanyard with the right hand, the hook between the thumb and forefinger, and stands ready to hand it to the gunner. IS^o. 4 mounts upon the chassis and, embarring through the ratchet-post with the elevating-bar, raises or lowers the breech as directed by the gunner. When the piece is correctly aimed, tiie gunner commands : Ready, makes a signal with both hands, removes the breech sight with his left hand, and, receiving the primer from ]^o. 3 in his right, inserts it in the vent, dismounts from the chassis, and goes where he can best observe the eff'ect of the shot ; jN'os. 1 and 2 break ofi* sideways with the foot farthest from the parapet ; N'o. 3 drops tlie handle, allowing the lanj^ard to pass through his fingers, steps back obliquely three yards to the rear, and breaks off to his left and rear with the left foot, left hand hanging nat- urally by the side ; N'o. 4 resumes his post, taking with him the elevating-bar, which he lays on the ground as before. 1. Number one (or the like), 2. Fire. 285. N"o. 3, turning his face from the piece, pulls the lan- yard quickly, but steadily, and fires. Immediately after the dis- charge, Nos. 1, 2, and 3 resume the erect position ; JS'o. 3 rewinds the lanyard and replaces it in the pouch. The gunner, having observed the eft'ect of the shot, returns to his post. 100-POUNDER PARROTT — SERVICE. 115 To load without the numbers^ and to fire. As explained in par. 245. To load and fire continuously^ and to cease firing^ As explained in ^ar^. 246 and 247. To secure the piece. As explained in par, 249. To replace equipments, 386. Executed as in par. 250, except that the gunner re- places the pouches on the ratchet-post, instead of the knob of the cascable. Note 1. — The piece may be fired with safety when the chassis is in gear. This part of the prescribed service may, therefore, be omitted. 2. The flooring-planks extend over but a portion of the chassis, making it exceedingly inconvenient to load the piece when in its proper position. To remedy this defect, cut boards to the proper length and fit them in crossways between the rails of the chassis, resting on the lower flanges of the rails. 3. Solid shot for this piece are without ears ; they cannot, there- fore, be carried by means of shell-hooks. The ladle for hot shot i{sometimes to be found at posts) answers for carrying and lifting the shot to the muzzle. Service of the 100-pounder Parrott. 28*^. The 100-pounder Parrott rifle is mounted on a carriage of similar construction to that of the 10-inch smooth-bore, and the service of it is nearly identical with the foregoing, except that, in bringing up the projectile, a rope strap is used instead of shell- hooks ; and excepting, also, that in pointing, No. 4, instead of using an elevating-bar, assists the gunner in giving the elevation by means of the elevating screw. Remarks. 288. All guns of the Parrott system are of cast-iron, i-ein- forced at the seat of the charge by a wrought-iron jacket, which IS shrank on. The one, two, and three hundred pounders have no preponderance. The depth of grooves in all of them is 0.10 inch, with increasing twist. The ;J00-pounder weighs 26,000 ponnds^; has 15 grooves. The *200-pounder weighs 16,800 pounds; has 11 grooves. The 100- pounder weighs 9,700 pounds; has 9 grooves. Tiie charge for 116 100-POUNDER PARROTT — SERVICE. the first is 25 pounds, for the second 16 pounds hexagonal, and? for the third 10 pounds cannon powder. Ranges: \00-poundcr. Charge : 10 pounds cannon powder. Projectile : Parrott shelly, filled, 100 pounds. Initial velocity : 1.080 feet. •AXIOOI m o C0«0'*OCf?»^eCr-llftC5100:i»-r-lt-l«Ort0»05000 i-(r-lr-t •iHOiT^i so atKix w 8 «Aooc5i-i'<#t-r-'-iioc5eocoooco«sooecoooor)i I— l-rtlmOOl— (TtlCOOOl— l-^t^OOi— HC;»-00-»-»~l-00000000O5CSO>O> •noixvAaiac o «OTtr-IOOCS00t~OI-l-t-Ot^t~00O0» C0»00i-(CO»000(?r-r-t-t~ooooooooo»o> •aoKTH t oo»ooooooooooooor-ooo«oo o o CO o o o lo o o o r- o o o eo o o o lo o r-ooooojO'— ii— ic^coTtcTtiio«or— r-oociOOi— 1 i-lr-li-(iHO*0««0*04(?*osc%o»o»o» "ITV J ^o aiOKV o -^orto «» t- t^ oo OS o 1— 1 T-i 0) Charge. w P^ W P^ H Deg's. Y'rds. Deg's, Y'rds. Sees. 100 pounds of mammoth 1 769 1 600 1.44 powder for solid shot, and 2 1332 2 1073 2.79 60 pounds for shell. 3 1819 3 1467 4.1 4 2235 4 1800 5.28 To fill shell: 12 pounds of 5 2601 5 2094 6.44 mortar powder. 6 2926 6 2355 7.58 7 3221 7 2590 8.07 Pressure per square inch, av- 8 3491 8 2804 9.68 erage, 19,500 pounds. 9 3735 9 3000 10.69 10 3959 10 3171 11.63 Length of cartridge : 15 4890 15 3916 16.30 100 pounds=30 inches. 20 5579 20 4458 20.52 60 pounds=18 inches. 120 15-INCH GUN — CENTRE PINTLE — SERVICE. CouQterpoise handspikes (iron) Truck handspikes (iron)... > Elevating-bar (iron) Sponge .. , Rammer Primer-pouch. Gunner's pouch. } The piece admits of 25 degrees elevation and 6 degrees depres- sion. The platform is a permanent portion of the work. To serve the piece. 394. Twelve men are required : one chief-of-detachment, one gunner, and ten cannoneers. The implements and equipments are arranged as follows : One on each side of piece, attached to socket on front axle by a set- screw. A rope is attached to the small end of tliese handspikes for heaving on when running the piece from battery. When not in use, the free end of the rope is hung by an eye to a hook on the cheek of the carriage. Two on each side of piece ; on hooks upon the sides of the chassis. Lying on the cari-iage, upon the rear notches, and perpendicular to the piece, handle to the left. One yard behind the cannoneers of the right ; the sponge and ram- mer-heads turned from the para- pet, inclined slightly fi-om the piece, and supported on a prop. Pass-box Two yards in rear of No. 7. ") Containing friction - primers and lanyard ; hung on step of the ratchet-post. Containing breech sight and prim- ing-wire ; hung on step of ratchet- j post. Chocks (iron) One on each hurter. Vent-cover Covering vent. Tompion In muzzle. Carrying-bar (wood) Two yards in rear of ^o. 10. Shell-hooks Two yards in rear of N'o. 4. Sponge-bucket l!^ear sponge. °Sra,!d''S.-.°:". } Attached to the crane. There not being suflScient space for them when the carriage 15-INCH GUN — CENTRE PINTLE — SERVICE. 121 runs from battery, neither handspikes, elevating-bar, nor any equipments will be placed on the floor-boards of the chassis. Wlieh several pieces are served together, there will be one quadrant^ one worm, one ladle^ one hammer-wrench^ two vent- punches^ one gunner'' s pincers^ two lanyards (extra), and two vent-gimlets to each battery of not exceeding six pieces. Tiiese will be kept in the filling-room of the service magazine. The cartridges are in the service magazine, and are brought to the piece as wanted. The shells are in the filling-room of the service magazine, and are likewise brought up when required. The shells are strapped to sabots. The fuse-plugs are of metal, and at the time of inserting the shell into the piece the paper cap should be pulled from the top of the fuse-primer. The solid shot are kept convenient to the piece. The projectiles should be carefully freed from dirt, lumps of rust, or any other pri^iuber- ances that might prevent their easy insertion into the bore of the piece. To distribute the equipments, 295. The instructor commands : 1. Take equipments. The gunner mounts upon the chassis, takes off' the vent- cover, hands it to No. 2, who places it against the parapet, near his post ; gives the primer-poucii to No. 3, equips himself with his own pouch, and clears the vent; Nos. 1 and 2 remove the plugs from the front ends of the air-cylinders. Nos. 5 and 6 hook the ropes to the counterpoise handspikes, and, securing the free end to the hooks on the cheeks, mount upon the chassis. Under the direction of the gunner. No. 6 takes the elevating -bar, embars with it through the ratchet- post, and, assisted by No. 5, gives tlie piece an elevation of about one degree ; replaces the elevating-bar, and, together with No. 5 and the gunner, resumes his post. The service of the piece is executed as follows. The instructor commands : 1. From battery. 296. The gunner mounts upon the chassis, and commands: In-gear. Nos. 3 and 4 adjust the pawls of the counterpoise handspikes so that they will clear the ratchets of the truck-wheels; Nos. 5 and 6 take down the ropes and raise the handspikes until Nos. 3 and 4 engage the pawls in the ratchets. In the meanwhile, Nos. 9 and 10 insert each a handspike into the sockets of the rear truck-wheels, and, mounting upon the 122 15-INCH GUN — CENTRE PINTLE — SERVICE. steps of the chassis, unlock the rear axle, and at the command Heave from the gunner, assisted by j^os. 7 and 8, throw the rear truck-wheels in gear. IS'os. 9 and 10 relock the axle, and return the handspikes to- the hooks. The gunner then commands : Embar. Xos. 5 and 6 raise the counterpoise handspikes until nearly vertical, when N'os. 3 and 4 engage the pawls into the ratchets. N'os. 3 and 5 seize the counterpoise handspikes, and N"os. 7 and 9 the ropes on the right of the piece ; and !N"os. 4, 6, 8, and 10 apply themselves, in like manner, upon the left. AH take hold from front to rear in the ascending order of their numbers^ At the command Heave from the gunner, the handspikes are forced down, and the top-carriage moves a short distance to the rear. JTos. 1 and 2 follow up the movement and keep the wheel- chocks closely applied to the wheels. The gunner gives alter- nately the commands embar and lieave^ until the muzzle of the piece is over the front part of the chassis; he then commands : Halt. At this command, Nos. 3 and 4 clear the p^wls from the ratchets, and Nos. 5 and 6 raise the handspikes and secure the ropes to the hooks. The gunner then commands : Out-OF-GEAR. Nos. 9 and 10 mount upon the steps of the chassis, unlock the axle, and, at the command Heave from the gunner, throw the wheels out of gear,, and, leaving the handspikes in the sockets, resume their posts. 1. By the numbers^ 2. Load. 29 T. ISTos. 1 and 2 mount upon the front of the chassis and upon the steps of the parapet wall ; No. 2 removes the tompion and hands it to '^o. 4, who places it against the parapet, in rear of the post of No. 2. No. 3 brings up the sponge, passes it to No. 1, and mounts upon the steps of the parapet wall, outside of No. 1, to assist Nos. 1 and 2 in sponging and ramming. The sponge-head is inserted in the muzzle. No. 5, bringing up the rammer behind No. 1, stands ready to hand it to No. 3, and to take the sponge from No. 3 after the sponging is completed. Nos. 7 and 9, taking the pass-box, go for the cartridge ; Nos. 4, 6, 8, and 10 go for the projectile, No. 4 carr3'ing the shell- hooks and No. 10 tiie carrying-bar. In returningv the projectile is brought up on the left of the piece. No. 4 in advance and the other numbers in their order in rear. The cartridge, in the pass-box, is brought up on the right of the piece. 15-INCH GUN — CENTRE PINTLE — SERVICE. 123 The projectile is placed under the crane; the carrying-bar re- tni-ned to its place by No. 10, who then resumes his post; the pulley is attached to the shell-liooks by ISTo. 4; Nos. 6 and 8 rnn lip tiie projectile, l^o. 4 steadying it. In the meanwhile — the gunner stopping the vent — the sponging is executed by I^os. 1 and 2, assisted by No. 3, at commands from the instructor of two — three— four^ &c. Two. Insert the sponge as far as the hand of N"o. 1, bodies erect, shoulders square. Three. Slide the hand along the staff and seize it at arm's- length. FOUB. Force the sponge down as prescribed for two. Five. Repeat what was done at three. Six. Push the sponge to the bottom of the bore. !N"o. 1 seizes the staff witli the left hand, back up, six inches nearer the muz- zle than the right ; No. 2 places the right hand, back up, between the hands of No. 1 ; both then change their other hands so as to grasp the staff with backs up. 1. Sponge. 29 S. Nos. 1, 2, and 3, pressing the sponge firmly against the bottom of the bore, turn it tln-ee times from right to left, and three times from left to right. The sponge is withdrawn at the commands two — three— four— Jive^ &c., b}'^ motions contrary to those prescribed for inserting it. As soon as tlie sponge is with- drawn, No. 3, turning towards the left, passes the sponge, with both hands, behind No. 1 to No. o, and receives from liim the rammer; Nos. 1 and 2 take the cartridge from Nos. 7 and 9, and insert it in the bore ; Nos. 7 and 9 replace the pass-box and i-esume their posts ; No. 5 replaces the sponge on the prop and resumes his post ; as soon as the cartridge is inserted. No. 3 places the rammer-head against it in the bore. The cartridge is forced down by Nos. 1, 2, and 3, at the commands and by the motions prescribed for the sponge. 1. Ram. 1299. The cartridge is set home by strong pressure, not hy a blow; Nos. 1 and 3 throw out the rammer; No. 2, quitting the staff, assists No. 4 in swinging the crane round to bring the projectile in front of the muzzle ; the rammer-head is placed against the projectile, whicii is pushed into the bore by Nos. 1, 2. 3, and 4; No. 4 withdraws the shell-hooks, and resumes his post; Nos. 1, 2, and 3 force the projectile home by motions and commands as explained for the cartridge; Nos. 6 and 8 swing the crane back; secure it and the pulley against the cheek; No.. 124 15- INCH GUN — CENTRE PINTLE — SERVICE. S resumes his post, and I^o. 6 mounts upon the chassis. The rammer is tin-own out and passed by No. 3. to ^"0. 5, who places it on tlie prop; INTos. 1, 2, 3, and 5 then resume tlieir posts. The gunner, assisted by No. 6, gives the piece an elevation of about five degrees, after which he pricks the cartridge, leaving the priming-wire in the vent. No. 6 resumes his post. 1. In battery. 300. The gunner commands: In-GEAR. Nos. 1 and 2 un- chock the wheels; Nos. 3 and 4 see that the handspike pawls are clear of the ratchets; Nos. 9 and 10 mount upon the steps, unlock the axle, seize the rear handspikes, and, at the command Heave bj'^ the gunner, bear down slowly (assisted if necessary by 7 and 8) until the piece is in motion, and regulate it by alter- nately throwing the wljeels in and out of gear sufficient!}^ for that purpose. The front wlieels are not chocked by ISTos. 1 and \2 unless the gunner so directs. As soon as the cari-iage strikes the hurter, the gunner commands : 1. Out-of-gear, 2. Heave. Nos. 9 and 10 throw the wheels out of gear, secure the axle with the pawl, and, returning the handspikes to the hooks on the chassis, resume their posts. Should the carriage not move when the wheels are thrown in gear, the gunner directs ]^os. 3, 4, 5, and 6 to lower the hand- spikes and engage the upper arm of the handspike pawl in the ratchet, and by raising the handspike urge the piece forward. 1. Aim. 301. The gunner commands: 1. CHASSIS in-Gear, 2. Heave. Xos. 7 and 8 take the handspikes, embar in the sock- ets of the eccentrics of the chassis, and, assisted by N'os. 9 and 10, throw the wheels in gear; they then embar with the same handspikes in the mortises of the rear set of the front traverse- wheels ; Nos. 1 and 2 embar in the front set ; Nos. 5 and 6 mount on the chassis to assist the gunner in giving the eleva- tion ; No. 3 passes the hook of tiie lanyard through tlie eye of a primer, and stands ready to hand it to the gunner. The gunner places the breech sight in the socket, and, sight- ing through it, gives the direction, commanding: Muzzle RIGHT, or Muzzle left, for Nos. 1, 2, 7, and 8 to traverse the chassis to the right or to the left. The direction" being given, the gunner commands : 1. Chas- sis out-of-gear, 2. Heave. At the first command, Nos. 1 and 2 return their handspikes to their hooks and resume their posts ; Nos. 7 and 8 embar in the sockets of the eccentrics of the chassis, and, assisted by Il^os. 9 and 10, at the command 15-INCH GUN — CENTRE PINTLE — SERVICE. 125- Ae«2;e throw the chassis out of gear; Nos. 7 and 8 then replace- their handspikes, and, with Nos. 9 and 10, resume then- posts. Note. — The piece can be fired with safety when tlie chassis is in gear. The omission of this part of the exercise saves much time and labor. The gunner next causes No. 6, assisted by N"o. o, to give the required elevation to the piece, and commands : Ready. Xos. 5 and 6 resume their posts, No. 6 taking with him the elevating- bar, which he places in rear of him on the ground, perpendicular to the piece. The gunner withdraws the priming-wire, receives the primer from Ko. 3, inserts it in the vent, takes the breech- sight with him, and goes where he can best observe the eftect of the shot. The chief-of-detachment, or in his absence the gunner, then commands: 1. Detachment bear, 2. March. At the first command, the cannoneers, except No. 3, face from the epaul- ment, and, at the command march^ they march to the rear as explained in par. 113; No. 3 drops the handle, allowing the lanyard to pass through his fingers, and steps back three j^ards obliquely from the piece, breaks off with his left foot to his left and rear, the left hand by the side. 1. Number one (or the like), 2. Fire. 302. No. 3, turning his face from the piece, pulls the lan- yard quickly, but steadily, and fires; immediately after the dis- charge he resumes the erect position; rewinding his lanyard,, returns it to his poucli and joins ins detachment. The gunner, having observed the effect of the shot, returns to liis post. As soon as the piece is discharged, unless otherwise directed, the cannoneers resume their posts by command of the chief-of- detachment. or in his absence the gunner : 1. Cannoneers to your- posts., 2. Right., 3. FACE, 4. MARCH. Executed as explained in par. 108. To load witliout the numbers^ and to fire, 303. Executed as prescribed in par. 245. To load and fire continuously, and to cease firing. 304. Executed as explained in pars. 246 and 247. When the piece is loaded, and it is not desired to fire it, the charge is withdrawn as explained in par. 289. To secure the piece. 305. Executed as explained in par. 286, adding: The gunner hangs the pouches on the ratchet-post, Nos. 1 ancR 126 15-INCH GUN — FRONT PINTLE — SERVICE. .2 replace the plugs in the front ends of the air-cylinders, and JN'os. 5 and 6 detach the ropes from the handspikes. Service of a 15-tnch G-un mounted on a front- pintle CARRIAGE. Description of piece. 306. This piece is identical with the same gun mounted on a centre-pintle carriage. {Par. 293.) The top-carriage is the same in both cases ; the chassis alone ■differs. Weight of front-pintle chassis, including geared traverse- wheels, 17,000 pounds. There are two kinds of geared traverse-wheels, differing, how- ever, only in height and weight. The axis of the trunnions of the gun mounted on the highest is 8 feet 5.25 inches above the pintle-block, and 10 feet 11.25 inches above the terre-plein. Upon the other carriage it is 7 feet 2,25 inches above the pintle-block, and 9 feet 5.25 inches above the terre-plein. The piece admits of 25 degrees elevation and 6 degrees de- pression. The platform is a permanent part of the work. The ranges are as given in par. 293. The same number of men are required as for the gun mounted on a centre-pintle carriage. The implements and equipments are likewise the same. Service of the piece. 307. Executed as for the centre-pintle carriage {pars. 295 to 305), except as follows : 1st. After what is prescribed under the head ram has been completed, and before the piece is run into battery, the gunner commands : 1. Chassis in-gear, 2. Heave. At the first com- mand, N'os. 3 and 4 embar with the handspikes in the sockets of the chassis eccentrics, and at the second command, assisted by I^os. 1, 2, 7, and 8, throw the wheels in gear. 2d. At the command aim^ the direction is given (under the direction of the gunner) by Nos. 7, 8, 9, and 10, who man the •cninks of the geared traverse-wheels. At the command Chassis OUT-OF-GEAR, Heave, the chassis is thrown out of gear by Xos. 1, 2, 3, 4, 7, and 8, J^os. 3 and 4 embarring with the handspikes. The piece is then run into battery as explained in par. 300 ; 15-INCH GUN — FRONT PINTLE — SERVICE. 127 after which the elevation is g,iven as explained in same para- graph. JSfote. — Tlie piece can be fired with safetj" when the chassis is in gear. The omission of this part of the exercise saves mnch time and labor. Remarks. 308. The foregoing instructions, for both the front and the centre pintle carriages, are for those of the most recent model. There are, however, in service, various patterns, — steps in im- provement,— the chief difference between them being in the arrangement of the means for running the piece from and into battery. Only slight modifications in the foregoing instructions are necessary to adapt them to any of the patterns, and these will readily suggest themselves to the instructor. The front axle of the top-carriage is not eccentric ; the rear one is. The front part of the sole of each shoe is cut away to a point a few inches in rear of the front axle, and to a depth ot .•ibout half an inch. When the rear wheels are out of gear, the front wheels do not touch the chassis rails ; but when the rear wheels are thrown into gear, the rear part of the carriage is slightly raised, and the front part of the carriage is, in conse- quence of the soles being cut away, lowered; the front wheels then touch the chassis rails and support the weight of the front part of the carriage, and the whole moves with rolling, friction upon the front and rear truck-wheels. The wheels are out of gear when the gun is fired ; the recoil is then on sliding fric- tion. The front axle is furnished, at each end, with a brass sleeve, to which the counterpoise handspike is firmly attached. A pawl is attached to the handspike, and engages into ratchets in the truck-wheels. Bearing down upon the handspikes forces the wheels to turn, and communicates motion to the carriage. The handspike pawls are engaged in the ratchet of the truck- wheels onl}^ when it is desired to give motion to the carriage ; at all other times they must be kept clear of the ratchets. Tliis is accomplished by a spring catch attached to each one, and ma- nipulated by ]N"os. 3 and 4 on their respective sides. To prevent the rear truck-wheels of the carriage from working out of gear while the gun is being run from battery, or jumping in gear when the gun is fired, pawls are provided for locking the rear axle. The elevation is given by means of the elevating arc. With a well-instructed detachment, the 15-inch gun can be fired twelve times in an hour, allowing time for deliberate point- ing. 128 FLANK-CASEMATE HOWITZER — SERVICE. The carriage and chassis for the front and centre pintle have the same dimensions, viz.: Length of chassis 19 feet 7 inches. Widtli of chassis 5 feet 2 inches. Depth of chassis rail 1 foot 8 inches. Length of carriage.. 8 feet 8 inches. Inclination of chassis rails 3 degrees. Service of a 24-pounder Howitzer mounted on a flank-casemate carriage. {Fig, 2, Plate 8.) Description of Piece. 309. Howitzer, cast-iron ; smooth-bore ; chambered ; muz- zle-loader. Designation. Calibre Weight Preponderance Length of piece Length of bore (in calibres) Length of chamber Diameter of chamber Windage Charge (cannon powder) Shell (empty) Weight of canister Carriage (top and chassis), wooden ; without re- coil checks No. 9.15 Lbs. 1475 70 2 16 20.5 Inch. 4.75 4.62 0.14 Kanoes in yards. Case Elevation. Shell. Shot. Time. Chakgb 2 IiBS. Oo 0' 295 Canister is used for sweeping 1° C 516 the ditch in front of the cur- 20 0' 600 2> tain ; and for this the piece 3° 30' ...... 880 3^ should be depressed 1 to 2 5° 0' 1322 degrees. 5° 30' 1050 4^ The piece admits of 7 degrees elevation and 9 degrees depres- sion. The platform is a permanent part of the work. FLANK-CASEMATE HOWITZER — SERVICE. 129 To serve the piece. Four men are necessary : one chief-of-detachment, one gunner, and two cannoneers. The implements and equipments are arranged as follows : Roller handspike (iron)... } ^^iXi'^To't'" "" """'" '''''"' "^ } Leaning against the scarp wall, be- Sponge and rammer [■ hind No. 1; the rammer-head upon the pavement. } Containing breech sight, chalk and chalk-line, and priming-wire ; sus- pended from knob of cascable. Cartridge-pouch Suspended from knob of cascable. } Containing primers and two lan- yards; suspended from knob of cascable. Sponge-bucket Behind and near N'o. 1. Vent-cover Covering the vent. Tompion In the muzzle. } Containing cartridges; at the safest and most convenient place near the piece. When several pieces are served together, there will be one worm, one ZacZZe, one hammer-wrench^ two vent-punches^ two vent-gimlets^ and one gunner''s pincers to each battery of not exceeding six pieces. These will be kept in the filling-room of the service magazine. The rounds of canister are arranged against the scarp wall, behind No. 2. The shells are at the filling-room of service mag- azine, or other safe position, and are brought as required to the place prescribed for the budge-barrel. They are strapped to sabots. The fuse-plug is of wood. To cause the equipments to he distributed, 310. The instructor commands : 1. Take equipments. The gunner equips himself with his own pouch ; gives the primer-pouch to No. 1 and the cartridge-pouch to No. 2 ; takes ofi" the vent-cover, and places it against the scarp wall beside the canister; applies his level to ascertain the highest point at the breech and muzzle, and, with the assistance of No. 2, snaps 9 130 FLANK-CASEMATE HOWITZER — SERVICE. the clialk-line to mark the line of metal; clears the vent; takes the roller handspike in the right hand, and resumes his post, holding the handspike vertically by the right side, its lower end on the pavement, the arm extended naturally. !N'o. 1 equips himself with the primer-pouch. ISTo. 2 equips himself with the cartridge-pouch, which he wears from the left shoulder to the right side. The service of the piece is executed hy the following commands from, the instinictor : 1. From battery. 311. The gunner, embarring in the left mortise, presses the roller under the rear transom, and, holding down the handspike with his right hand, seizes the left handle with the left ; Xos. 1 and 2 lay hold of the manoeuvering rings and handles. All being ready, the gunner commands : Heave, and the car- riage is run to the rear until the face of the piece is about one yard from the wall, when, disengaging the roller, he commands Halt, leaving the handspike in the socket. All resume their posts. 1. By the numbers^ 2. Load. 312. The gunner places himself at the breech; breaks to the rear with the right foot; closes the. vent with the second finger of the right hand, and manages the elevating screw with the left. N'o. 2 removes the tompion and places it against the scarp, near his post. iSTo. 1 seizes the sponge-staff at its middle, brings it across his body, plants the left foot opposite the muzzle, close to the carriage, and breaks off with the right foot ; at the same time throwing the sponge-staff into the left hand, back down, and extending both hands towards the ends of the staff, enters the rammer-head into the embrasure, introduces the sponge into the muzzle, and drops the left hand by the side. He then forces the sponge to the bottom of the chamber with three motions, at the commands TWO— three — FOUR. N'o. 2 goes for a cartridge and returns to his post. If shells are used, he brings a shell at the same time. 1. Sponge. 313. [N'o. 1, using both hands, backs up, sponges the cham- ber carefully, withdraws the sponge, pressing it against the lower surface of the bore ; turns it over, stepping to his left for this pur- pose, and rests the rammer-head against the right side of the FLANK-CASEMATE HOWITZER — SERVICE. 131 ■face of the piece, back of the right hand down, that of (he left up. No. 2 introduces the cartridge. No. 1 sets it home by the same commands and motions as for sponging. 1. Ram. 314. jN"o. 1, throwing the weight of his body on the staif, forces the cartridge tightly home and throws out the rammer, holding it as before, the rammer-head against the right side of the face of the piece. No. 2 introduces the canister or shell, and resumes his post. No. 1 sets the canister or shell home with care ; throws out the rammer, replaces it, and resumes his post. The gunner, rising up, pricks, leaving the priming-wire in the vent, and resumes his post. 1. In battery. 315. All apply themselves to the carriage as prescribed in par. 311, and ease the piece into battery. As soon as it touches the hurters, the gunner commands : Halt, and all resume their posts. 1. Aim. 316. No. 1 makes ready a primer; No. 2 goes to the rear of the chassis, and takes hold of it to traverse it. The gunner with- draws the priming-wire ; aims the piece, directing No. 2 to tra- verse it to the right or left; gives the command Ready, making a signal with both hands, at which No. 2 resnmes his post ; takes with him the roller handspike and resumes his post. No. 1 in- «erts the primer in the vent and steps back obliquely tlu-ee yards to the rear, and breaks oft' with the left foot to his left and rear. 1. Number one (or the like), 2. Fire. 317. No. 1, turning his face from the piece, pulls the lanyard and fires it; he then resumes his post. To load without the numbers,, and to fire. To load and fire continuously., and to cease firing. To secure the piece. Executed as explained for the siege gun, m pars. 245, 246, ^nd 247. Remarks. 31$. In repelling assaults, double charges of canister are iised ; the charge of powder remaining the same. The effective range of canister is not over four hundred yards. 132 8-inch rifle — service. Service of an 8-incii Eifle (converted). Description of gun. {Fig. 2, Plate 3.) 319. This piece is composed, essentially, of two parts: the- case^ f, which is the 10-inch smooth-bore (described in par. 276> bored up to a diameter of 13.5 inches, and a lining-tube of coiled wrought-iron. The tube consists of two parts, called, respectively, the A and B tubes. The former extends the entire length of the bore, and contains the rifling; the latter, or B tube, is shrunk upon the inner, or A tube, which has its exterior portion cut away for that purpose. A double tube is thus formed, extending 32.75 inches from the rear end. The two tubes, united in this manner, have the same exterior diameter throughout the entire length, and are made to fit accurately the bore of the cast-iron casing. The bottom of the tube is closed with a wrought-iron cup- shaped plug, p, screwed into the A tube. The tube is inserted into the casing from the muzzle, and is secured from working out by a muzzle-collar, 5, screwed in at the face of the piece ; and from turning in the casing by a steel pin, ';^, tapped through the casing and into the tube. A shallow and narrow gas-channel is cut spirally around the exterior of the reduced portion of the A tube, communicating with star-grooves cut in the end of the barrel, and with the gas- escape, or indicator^ bored obliquely through the breech of the casing opposite the vent. Should the inner tube split, under the action of firing, the fact w^ould be indicated by the escape of gas through this hole, and timely warning thus be given of the injury sustained by the gun.. The rifling consists of fifteen lands and grooves, each of equal width, viz.: 0.8377 inches. Depth of grooves: 0.075 inches- Twist : uniform, one turn in 40 feet. There is no chamber proper to the gun. The rifling stops at a point 10 inches from the bottom of the bore, the diameter of the unrifled portion being equal to that of the rifled portion across lands. The old vent of the case is closed by a wrought-iron screw- plug, and 2.75 inches nearer the muzzle a new one is bored par- allel to tlie vertical plane through the axis of the bore, and dis- tant therefrom 2.5 inches. The axis of the vent enters the bore at 3.5 inches from the bottom. Length of bore 117.25 inches. Weight of piece 16,160 pounds. Counter-preponderance 630 pounds. 8-INCH RIFLE — SERVICE. 183 The counter-preponderance is corrected b}' an eccentric ring of bronze attaclied to eacli trunnion. Weight of projectile (averaj^e) 180 pounds. Weight of ciiar2:e (hexagonal powder) 35 pounds. Initial velocity 1.430 feet. Pressure upon square inch of bore 33,000 pounds. Penetration against armor at 1000 yards.... 7.42 inches. Penetration against armor at 1800 yards.... 6.75 inches. Ranges. Charge : 35 pounds hexagonal powder. •XiHaa •AxiooiaA OOOOOC:>0)0»0)CiOC:0>O0)CiC3C330»0:0»C3OO00000000 p4 00>OOi-H»^«Ot-00«OOOi-r500i— (I— lrJ(CJTt£S Svt Tt* O 1— I O* ■^ O CO CO lO I— ( Ttl O O O* »£5 iH c^ o la ITS «o o «o «o i— t- 1» r- 00 00 OS OS C5 OS o o o iH T— I (M Ttio«oocc»oomoo(?*«oeo CJ irsooi— (OTtit-occ»r5«ocic-l 7/) «£> t- 1^ t» t~ c» oo oo oo 00 ci cs cs C5 o o o o 1— ( 1— 1 1— I c<» c< (M e<» ec eo «, O--+<00O(M«>OlftOOmO»f5OO«0G^00O'^O«0O'^(MO00O co-^inoi— i(MM<»r50i— id-'S'irsoi— lisi-rtiiooi— ico-^oocv»TjHirso O TjH •* Tfi lo LS «fl in ITS «o «£> «o «o «o r- 1- 1:- t- 1- oo 00 oo 00 crs OS o o OS O m oootr-oooocooooocooooot-ooot^ooooeo 'J sot— oococsO'— ic^-T-fCO-nfurscoeot-oooscsOi— icMCOco-^irseot-t- fH (M 0C» » Ot CO CO 00 CO CO CO CO CO CO CO CO CO rj< rn -^tt ■* rti TTI rji Tji T}( Tji Tf m I— icob-(»csooooOt— iioMOr-(coeooo»«ifl«oO(?*iftm«oo«DOO»ftia r^ oo o I— 1 1— 1 oj CO ■* irso »o (?* Tfi -^ toc5o»iO'o I— I cv« too in cscv« -"H OS (h oo'ooooooooOl-^I-^rHl-^r^^^oi(^^<^^eocoeo•«^Tt!T)^»alO^£i o oo«o>0'^coeo'^<>*m«oooocot— lOrHioos'^Oi— icDcoot— «ocsm»o Oi oi o oo «o 'I' o* o o 00 «3 ■<# CO I— ( OS cs 00 eo M< CO GJC^»C>C0(M«-li— (T— li— (r-'i— tl— lr-(r— lOOOOOOO g ^^^^^^^^^^^^^^^^^^^^^^^^^^^.^^ ^ oosoift'Tcoo-ioocoTtiioeoi— ocorftoi— i«oi— isocoi— i«ocC'Oi— r-'^i— I Or^C^C0"^10OOi— (CsiCOTPOrHrHC^TjfuSr-IOiCO'^in.-lCOTjilOOO* O O O O O O O iH iH i-l rH 1-1 ^ « (M O* 04 (M 04 ec CO CO CO CO Tt< Tjl T}< TjliO tC 1— I c^ CO JO I~ OS <>» »ft lO OS CO t- 0<» t- O (?* OO •'l^ O t- -^ rt* r-l OS t— m CO rft CO O (?»10lOt-Oi(MTtll^C;0(MTtlt-OC^T)HlOOOOCO«CiOOOSO* yj o'oOO^-^l--Jr4r-^l-1r-l(^i!^J(^»(^jcOCOCOCOrl^rJ^rl^■^a^T]il^jlO ». OO eO ■* 05 rH O OS O 00 00 00 00 OO 00 O OS O rH CS» CO O -rt< so 00 O 0<» O ■-t 0< CO ■^ in ITS O O r-< i?< CO Tji lO O O (?* CO ■«i< »0 O O r-( <>» Tji la O O >-( O O O O O O O O tH rH rH i-l i-l i-< i-H 04 (?* !M 04 (>» (M CO CO CO 00 CO CO ■* r}( rjt r/J OOOOOOOCSOOOOOOr-HOOOOOCOOOOOOinOO frt o ooooooooooooo^ OC2OOO50OOOO c; •vso o ly r-<(?ico'^io?or-t^i»osc3i— (<>icocOTtim«or-cooooscii— (<>jcocoT^irt pH rH I— I I— t i-H I— ( T-l l-H r-* ?-l I— I !—( I— I <>» Ov» a* (M Cs» •NoixvAaia: •aoiiYH •i^uHo: •AxiooiaA OKLsriVMaH "XHsn^i ■iO awijj •KOixvAaia •aoMva 134 8-INCH RIFLE — SERVICE. It has been found that the 10-inch carriage, upon which this^ piece is mounted, is not sufficiently stout to stand many dis- charges with a charge of 35 pounds. Charges of 25 pounds will penetrate any wooden ship at or- dinary ranges, but are of no effect against iron-clads. The car- riages will stand this charge without serious damage. Ranges. Charge : 25 pounds hexagonal powder. •i^HQ M C5cooi-iootoeoooj«* f^ iOr-it-OCOC5»0 oo oo 1-1 I-H iH . CO -^ lO (M CO t^ cs 1— 1 ci CO lO t- o o CO «o C5 o CO r«- ^ oo to CO «0 C5 r-i OOO J/2 r-li-(iH •xoixvAaia ^ O-OO^JOOOTHOt-O-^iHOOOO-^tMOOOOt^eOO o TjH rji Tf< in lO o ic o «o CO «o CO t- »- r- 1- 00 00 00 CO 00 OS •aoxvH to o o o in o oo o r-io o o t- o o o C50 o o 0(M iP cici— ii— loico-^i-Qinot-oooociOi— ii-'tMcor)i Git O* (J* O* C4 OQ O* 0» 0< O* f shell (empty) Charge to fill shell, musket powder Charge to blow out fuse-plug Weight of carriage Weight of carriage, mortar, and implements. (One m ortar- wagon will carry three mortars, with th eir carriages.) Horses rtq^uired for above No. Lbs. Inch. 1010 00 2.25 46 2.5 0.25 900 1965 22 0.12 Ranges. Charge. Elevation. Range, Yards. Time of Flight. Seconds. Ounces. Degrees. Shell, 52 lbs. Shell, 46 lbs. SheU,521bs. Shell, 46 lbs. 8 45 399 433 9.50 9.65 10 45 717 727 12.45 12.50 lA 45 955 1029 14.85 15 14 45 1265 1275 16.50 16.80 The piece is tired from a wooden platform. {Par. 225.) To serve the piece. Four men are necessary : one chief-of-detachment, one gun- ner, and two cannoneers. The implements and equipments — omitting two handspikes and adding a grummet-wad — are the same as for the 10-inch siege mortar, and are arranged in the same manner. The grummel-wad is in the basket. 356. The service of the piece is the same as that prescribedj for the 10-inch siege mortar, with the following modifications : 156 8-INCH SIEGE MORTAR — SERVICE. At the command take equipments^ isTo. 1 performs the duties oi No. 3, and No. 2 those of No. 4, in addition to their own. No. 2 places the grnmmet-wad on the platform in front of the carriage, near the transom, and assists No. 1 to put on his sleeves. At the command in battery^ Nos. 1 and 2 embar under the front manoeuvering bolts, facing to the front. At the command from battery^ No. 1 embars under the right front manoeuvering bolt, and No. 2 under the left rear bolt, both facing from the parapet. If the carriage has no rear manoeuvering bolts. No. 2 embars under the left rear notch, nearly perpendicular to the cheek. In loading, No. 1, having wiped out the piece, clears the vent and, if necessarj^ sweeps the platform. No. 2, laying down his handspike and taking with him the shell-hooks, goes for a cartridge and shell, returns by the left of the piece, passes between the gunner and the muzzle, and, rest- ing the shell upon the wad, gives the cartridge to the gunner. The gunner, having poured in the powder, returns the car- tridge-bag to No. 2, and distributes the powder evenly over the bottom of the bore ; takes from No. 2 the shell-hooks, raises the shell and lowers it into its place in the bore. All j-esume their posts. At the command Aim, the gunner perfonns the same duties and gives the same commands as with the 10-inch mortar. (Par, 347.) For mortar right : No. 1 embars perpendicularly to the cheek under the right front notch, from within, and No. 2 similarly under the left rear notch, from without. Y or mortar left : No. 2 embars perpendicularly to the cheek under the left front notch, from within, and No. 1 similarly un- der the right rear notch, from without. For muzzle right : The same as for the 10-inch mortar. (Par, 347.) For muzzle left: The same as for the 10-inch mortar. (Par, 347.) For trail right: No. 2 embars perpendicularly to the cheek under the right rear notch, from the inside. For trail left: No. 1 embars perpendicularly to the cheek un- der the left rear notch, from the inside. In all of these operations Nos. 1 and 2 face towards the gunner and observe his signals. The direction being given, the elevation is given as prescribed for the 10-inch mortar {par. 347), except that No. 2 performs the duties therein prescribed for No. 4, and No. 1 those for No. 3. COEHORN MORTAR — SERVICE. 157 At the signal from the gunner, N"o. 1 prepares to fire as pre- scribed for No. 3 ill the exercises for the 10-inch mortar. {Par, 347.) Service of a Coehorn Mortar. {Fig. 2, Plate 9.) Description of Piece. Sd*?. Mortar^ bronze; hore^ smooth, with chamber; calibre^ 0.8 inches ; weight ofpiece^ 164 lbs. ; extreme lengthy 16.32 inches ; maximum charge, 12 oz. '•''mortar powder'''''^ weight of shelly. empty, 16.8 lbs. ; charge to fill the shell, 1 lb. ; to blow out fusey. 2 oz. The carriage is simply a block of wood, weighing 132 lbs. ;:. total weight of piece, equipments, and carriage, 311 lbs. Ranges. Charge. Eleyatiok. Projectile weighing 17.5 LBS. Time of Flight. Ounces. Degrees. Yards, Seconds. 2.0 45 84 4.0 45 261 5.0 45 425 6.0 45 548 6.5 45 666 7.0 45 840 7.5 45 980 8.0 45 8.5 45 i074 9.0 45 9.5 45 10.0 45 1*262 10.5 45 11.0 45 1316 12.0 45 1385 The carriage or block upon which the Coehorn mortar i» mounted, is provided with two handles on each side, by means- of which the mortar is readily carried by four men from one part 158 COEHORN MORTAR — SERVICE. of the work to another. They accompany troops in the field for use against an enemy covered by intrenchments. The ground, when firm, is sutBclent for the carriage to rest upon ; if it is not firm, a platform can readily be extemporized from such material as may be at hand. The carriage should be level when the mortar is fired. To serve the piece. 358. Four men are necessary : one chief-of-detachment, one gunner, and two cannoneers. The implements and equipments are carried in a basket, which is near and in rear of the mortar. They are as follows : Primer- pouch, containing priming-wire, primers, and lanyard; gunner's pouch, containing gunner's level and a pair of small pincers ; one quadrant, one sponge, one plummet, and one mallet. A small wedge is used as a quoin. The mortar should have a permanent line of metal marked upon it ; otherwise this must be marked as for the 10-inch siege mortar. {Par. 344.) The shells should be strapped with tin, apd be provided with •cord handle. They, together with the powder and fuses, are kept in the service magazine. The implements for preparing ammunition are the same as prescribed in par. 275. The service of the piece is analogous to that for the 10-inch siege mortar. {Par. 342 and following.) Remarks. 359. When Coehorn mortars accompany troops in cam- paign, they may be carried on ordinary field caissons; each cais- son carrying one mortar, together with sixty rounds of ammuni- tion. The mortar is carried on the caisson body, the front chest being removed for this purpose. The piece is securely lashed with ropes through the handles. The remaining ammunition chests are arranged to carry thirty shells each. The powder is in cans, and a set of measures (from one to six ounces) should be pro- vided. The shells should be charged and the fuse-plugs driven, ready for the insertion of the fuses. A caisson with chests similarly arranged should accompany each piece. The mortars may also be carried in ordinary army transporta- tion-wagons. Each wagon will carr}^ one Coehorn and its equipments (weighing 311 pounds), and sixteen boxes, each containing eight shells and weighing 168=2688 pounds — total, 2999 pounds : a fair load, on good roads, for four horses or six mules. 13-INCH MORTAR — SERVICE. 159 Battery of Six Coehorns. One captain, three lieutenants, six sergeants, six corporals, •eight drivers, thirty cannoneers, and thirty-two horses. When ordinary wagons are used instead of caissons, two one- Jiorse carts are allowed as tenders in bringing up ammunition, &c. An army operating in the field should be abundantly supplied Avith this handy and useful weapon. Service of a 13-inch Mortar (eccentric axle). {Fig. 4, Plate 9.) Description op Piece. 360. Mortar, cast-iron ; smooth-bore, without chamber. Designation". "Weight of piece - Preponderance Extreme length Length of bore Windage Charge (maximum), mortar powder. Weight of shell (empty) Charge to fill shell Charge to blow out fuse-plug Weight of carriage Lbs. Inch. 17,120 00 20 216 11 0.3 4,140 54.5 35.1 0.13 The mortar is fired from a wooden platform. {Par. 227.) The carriage is of wrought-iron, and, being without chassis, rests' di- rectly upon the platform. An axle, carrying at each extremity a truck-wheel, passes through the carriage near the front end ; this axle is eccentric, and when thrown in gear the truck-wheels rest upon the plat- form ; only the rear part of the shoe then rests on the platform and moves with sliding friction. Two steps are placed on the iront part of the carriage for convenience in loading. Ranges. Charge. Lbs, 10 10 15 20 10 15 20 Elevation. Range. Degrees. Yards. 30 2875 45 3187 45 3759 45 4636 60 2852 60 3378 60 3893 Time of Flight. Seconds. 19 25.8 28 31.75 32.75 38.75 39.16 160 13-INCH MORTAR — SERVICE. To serve the piece. 361. Eight men are necessary : one chief-of-detachment, one gunner, and six cannoneers. The implements and equipments are arranged as follows : Truck handspikes (iron) .. \ ^""^ ^H ^^^^ ^]^^^ hanging by hooks '^ "^ i on the cheeks. ] One on each side, lying on plat- Manoeuvering handspikes. I form against the cheeks, small (wood.) r ends to the front and resting on J the truck-wheels. Elevating-bar (iron) \ Lying on the carriage, over rear * ^ '' / notches, handle to the left. Wheel-chocks (iron) \ ^"1 ^^' ^.^^^ ^'^^^' ^^^ ^^® »Pi^^^ step ^ ' J of carriage. }0n prop, one yard in rear of No. 1 ; sponge - head towards the epaul- ment. Pass-box One yard behind N"o. 4. Quadrant 1 Plummet's 7th reeV I ^'^ basket, between the cheeks of Sleeves (two paiio"*. Z''Z \ ^^^ carriage, in rear. Shell-hooks J Tompion In the muzzle. } Containing the priming-wire, fric- tion-primers, and lanyard ; in bas- ket. Gunner's pouch \ Containing gunner's level, chalk ^ J and chalk-lme ; in basket. Sponge-bucket ^ Broom I With basket. Carrying-bar (iron) J Trestles (three) Kear epaulment, in front of piece. To each battery not exceeding six pieces there will be one hammer-wrench^ two vent -punches, one gunner'' s pincers^ two lanyards (extra), and two vent-gimlets. These are kept in the filling-room of the service magazine. The powder, primers, and fuses are kept in the service maga- zine, and the shells in the filling-room of the magazine. The implements for preparing the ammunition are those speci- fied in par. 275. 13-INCH MORTAR — SERVICE. 161 To establish the plummets in the plane of sight, the instructor commands : Place the plummets. Executed as for the 10- inch siege mortar. {Par. 343.) To distribute the implements and equipments, 362. The instructor commands : 1. Take equipments. The gunner goes to the basket ; gives to N^o. 1 the broom, the fiponge-bucket, and a pair of sleeves ; to IS'o. 3, the primer-pouch, and to ]S"o. 2 the carrying-bar and basket. N^o. 1 places the broom and bucket on the ground in his rear, and, assisted by l^o. 3, puts on a pair of sleeves. The gunner equips himself with his pouch and, assisted by N"o. 4, puts on a pair of sleeves ; then, applying his level, ascer- tains and marks the highest points of metal at the muzzle and near the vent. Between these points, assisted by No. 4, he snaps the chalk-line, thus marking the line of metal ; he then resumes his post. JSTo. 2 places the basket one yard behind him, and lays the carrying-bar and shell-hooks on the ground near it; No. 3 equips himself with the primer-poucli and clears the vent ; No. 4 places the elevating-bar behind him and perpendicular to the carriage ; Nos. 5 and 6 place each a manceuvering handspike on the ground perpendicular to the carriage, the small end resting on the edge of the platform and on the side of them next the epaulment. The truck handspikes, when not in use, remain on the hooks. The mortar being from battery. 363. The instructor commands : 1. In battery. The gunner places himself two yards in rear of the platform, facing to the i)iece, and commands : In-gear. Nos. 3 and 4 take the truck handspikes from the hooks and embar in the eccentric sockets ; Nos. 5 and 6 seize the handspikes above the hands of Nos. 3 and 4. The gunner commands : Heave and, as soon as the wheels are in gear, Embar, when the handspikes are placed in the most convenient rear mortises of the truck- wheels. The mortar is moved to the front as fai- as required by the alternate commands heave 'AxiOi embar ivom. the gunner; he then commands : Halt and Out-of-gear, and the handspikes are again inserted in the eccentric sockets. The gimner com- 11 162 13-INCH MORTAR; — SERVICE. mands : Heave, the wheels are thrown oat of ^ear, and the handspikes returned to their hooks. Nos. 3, 4, 5, and 6 then re- sume their posts. 1. From battery. Executed as above, except that the truck handspikes are in- serted in the most convenient front mortises of the truck-wheels at the command embar. 1. By the numbers^ 2. LoAD. 364. 1^0. 2 takes out the tompion and places it by the epaul- ment in rear of his post. The gunner places himself one yard in front of the piece, facing the muzzle. 'No. 1, facing to his right, takes the sponge-staff in his right hand, mounts upon the step, and passes the sponge to the bottom of the bore ; sponges with both hands, withdraws the sponge, replaces it on the prop, and resumes his post ; No. 3 clears the vent; No. 4, taking the pass-box, goes for a cartridge ; Nos. 2, 3, 5, and 6 go for the shell ; No. 2 takes with him the carrying- bar and shell-hooks, engages the shell-hooks in the ears of the shell, and passes the carrying-bar through the ring. In carrying the shell, ISTos. 3 and 5 are in advance, and IN'os. 2 and 6 in rear ; N^os. 2 and 3 are at the ends of the bar, using their right hands ; N"os. 5 and 6 use their left hands. The shell is brought up by the left side of the piece, and those carrying it, passing between the gunner and the muzzle, rest it on the step ; No. 4 hands the cartridge to the gunner, who pours the powder into the piece, and, using the spatula, distributes it evenly over the bottom of the bore ; he then returns the cartridge-bag to No. 4, who, putting it in the pass-box, resumes his post. The shell is raised b.y the numbers at the carrying-bar, and lowered into the bore until the bar rests against the face of the piece. The gunner seizes the shell-hooks, and, after No. 2 with- draws the bar, lowers the shell into its place, adjusting it so that the fuse will be in the axis of the piece ; disengages the shell-hooks, which he throws behind No. 2, and then resumes his post. No. 2 replaces the carrying-bar on the ground, and resumes his post. When necessary, the platform will be swept by No. 1. 1. Aim. 365. The gunner places himself behind the rear plummet to give the direction, and commands : In-gear — Heave— Em- bar. All executed as prescribed in par. 363. The gxinner then, sighting by the plummets, gives the direc- 13-INCH MORTAR — SERVICE. 16 o ■tion, commanding : Muzzle right; Muzzle left; Mortar right; Mortar left, according as desired. For muzzle right : ]N'os. 3 and 5 heave to the rear, and Nos. 4 and 6 to the front, at the command Heave from the gunner, wlio repeats the alternate commands heave and embar as often as nmy be necessary. For muzzle left : Same as above, except that Nos. 3 and 5 heave to the front and N'os. 4 and 6 to the rear. Mortar right (or left) is executed by giving the muzzle the proper direction and running the mortar in battery, or by giv- ing the muzzle the opposite direction and running the mortar from battery. In either case the manoeuvre is completed by throwing the muzzle in the proper direction on its platform by the commands alread}'' given. The direction having been given, the gunner commands : Halt, and the eccentrics are tin-own out of gear as described in par. 363. To prevent the carriage from moving out of line when the eccentrics are thrown out of geai", the wheels should be firmlj'^ chocked in front. This is done by Nos. 1 and 2 at the command halt. If necessary to rectify the direction of the piece after the eccen- trics are out of gear, the gunner causes ^N'os. 5 and 6, assisted by all the other cannoneers, to embar under the rear notclies with the manoeuvering handspikes and move the trail to the right or left. No. 3 pricks the vent and then prepares the lanyard and primer ; !N'o. 4 embars with the elevating-bar through the ratchet- post, and, assisted by IsTo. 5, raises or depresses the breech at the command of the gunner. The gunner applies the quadrant to tlie face of the piece, giving the commands to No. 4, Raise or Lower, until the piece is at the required elevation, usually forty-five degrees, makes a signal to No. 4, who then unbars, places the elevating-bar in its place on the ground, and resumes his post. The gunner commands : Ready, returns the quad- rant to tlie basket, receives the primer from No. 3, and, passing the lanyard under the pipe, inserts the primer in the vent, and goes where he can best observe the shot. The cannoneers, except No. 3, go at the command ready to the rear of the platform and form detachment as in detachment rear., leaving No. 4 uncovered; No. 3, holding the handle of the lanyard in his right hand, back of the hand up, moves tliree yards obliquely to his left and rear, and breaks oft* to his left and rear a full pace with his left foot, his left hand hanging naturally ■by his side. 1. Number one (or the like), 2. Fire. 366. No. 3, turning his face from the piece, pulls the Ian- 164: 13-INCH MORTAR — SERVICE. yard quickly, but steadilj^ and fires. On the discharge of the- piece, all except the gunner return — without command — to their posts; as soon as the shell strikes, the gunner returns to his post. When exercising for instruction only, the instructor continues it by causing the piece to be moved toward the rear of the plat- form by the command From battery. He then commands : 1. Unload. 36*7. The gunner, receiving the shell-hooks from No. 2, mounts upon the step of the carriage and attaches them to the shell ; N'o. 2 puts the carrying-bar through the ring of the hooks, and, assisted by Nos. 3, 5, and 6, raises the shell from the bore of the piece and carries it to its former place. In doing this, the cannoneers apply themselves as in bringing up tlie shell, but move in the reverse order. All then resume their posts. The instructor continues the series of commands, beginning with In battery. In changing posts, l^o. 2 passes by the front of the piece. To load without the numbers^ and to Jire. To load and jire continuously^ and to cease firing. Executed as in jpars, 246 and 247. To secure piece and replace equipments. Tlie instructor causes the piece to be placed on the centre of the platform, and commands : E'eplace equipments. 368. Nos. 5 and 6 replace the handspikes on the truck-wheels ;, N"©. 2 puts in the tompion and replaces the basket between the cheeks, in rear; N"o. 4 assists the gunner to take off' his sleeves; No. 3, in like manner, assists No. 1 ; the gunner receives the equipments f i-om the cannoneers and replaces them in the basket ; Nos. 3 and 4 replace the trestles and plummets. Remarks. If, in securing the mortar, the muzzle has been so far depressed that the elevating-bar cannot be engaged in the ratcliets, a trace chain may be doubled over the ratciict and the bar engaged in tlie bigiit of the chain ; or the elevating-bar may be placed in the ratchets perpendicular to the axis of the piece, and a wooden handspike engaged over the bar and under the nuts or T-plate& of the clieeks, and the mortar thus elevated. 10-INCH SEA-COAST MORTAR — SERVICE. 165 A bar known as Fiper^s loading bar is a far more conven- ient implement than the shell-hooks for carrying and loading the shell. It is simply a bar of round iron about two feet long, fashioned into a ring at one end for a handle, and having a screw •cut on the other end, which screws into a shallow hole tapped in the shell at a short distance from the fuse-hole. When the shell is lowered into the bore and adjusted, the bar is unscrewed and removed. To insure the ignition of the fuse of mortar shells, the end of the fuse-plug and the shell around it should be smeared with treacle, varnish, mucilage, or any other sticky substance, and after the shell is in the bore a little fine-grain powder thrown on it. In rainy weather, great care must be observed to keep the •charge dry during the operation of loading. This may be ef- fected by covering the piece with a paulin, the front part of which can be raised while the loading is going on. Service of a 10-inch Sea -coast Mortar (eccentric axle). Description of Piece. 369. Mortar, cast-iron; smooth-bore, without chamber. Designatio:n^. Calibre Weight Preponderance Lengtli of piece Length of bore VS^indage Charge (maximum), mortar powder Charge to fill shell Charge to burst shell Charge to blow out fuse Weight of carriage Lbs. 7300 00 12 5 2 0.5 2924 Inch. 10 47.05 32.5 0.13 The carriage is of wrought-iron, and is pi-ovided with an eccen- tric axle and truck-wheels similar to the carriage for the 13-inch mortar. {Par. 360.) The mortar is fired from a wooden plat- form. (Par. 228.) With heavy charges, the shell used in the 10-inch gun may be used for this mortar. The 10-inch siege-mortar shell may be ♦used with moderate charges. 166 10-INCH SEA-COAST MORTAR — SERVICE. Ranges. With 10-iiich siege-raortar shells, filled with sand (weight 96.5^ pounds). Ohabgb. Elevation. Range. TnVTR OF Flight. libs. oz. Degrees. Yards. Seconds. 5 45 2720 25.20 5 8 45 2983 26.33 6 45 3005 26.50 6 8 45 3254 26.75 7 45 3325 27.50 With 10-inch gun shells, filled with sand (weight 104 pounds). Charge. Elevation. Range. Time op Flioht. libs. oz. Degrees. Yards. Seconds. 7 8 45 3471 28.10 8 45 3638 29.60 8 8 45 3648 29.75 9 45 3677 30.75 9 8 45 4096 30.40 10 45 4301 31.25 10 8 45 4345 32.00 11 45 4458 33.50 11 8 45 4465 34.00 12 45 4536 not taken. To serve the piece. Six men are necessary: one chief-of-detachment, one gunner,, and four cannoneers. The implements and equipments are the same as for the 13- inch mortar {par. 301), omitting the sponge and adding a wiper, a wiper-stake, and a maul, and are distributed as in the service of the 10-inch siege mortar (par. 344), except that when there are no hooks on the cheeks for the truck handspikes, these ar(^ laid on the platform in front of ^N'os. 1 and 2, parallel to the cheeks, small ends to the front, and are returned to this posi— tion whenever not actually in use. 13-INCII MORTAR — CENTRE PINTLE — SERVICE. 167 The mortar is raanoeuvered on its platform as prescribed for the 13-inch mortar, and by the same commands. {Par. 363.) The loading and firing are executed as prescribed for the serv- ice of the lO-inch siege mortar. {Par, 346 et seq.) Service of a 13-inch Mortar (centre-pintle carriage). [Fig. 3, Plate 9.) Description of Piece. 370. This piece differs from the one described in par. 360 only in the method of mounting. Both have the same cari-iage, but instead of the carriage resting directly on the platform, as in the first, the carriage for the centre pintle is mounted on a chassis itself resting on the platform. The cliassis is attached at its centre to the platform by a pin- tle, and traverses upon iron circles in the manner usual for this class of carriages. In addition to the eccentric axle at the middle of the chassis, for throwing it in and out of gear, there is another axle, also eccentric, carrying a traverse-wiieel which works between the parts of a double transom on the front end of the chassis. This wheel communicates motion to the chassis. A crane is attached to the left cheek for hoisting the shell to the muzzle. The chassis has an inclination to the rear of three degrees ; it is of wrought-iron, and weighs 5560 pounds. The ranges are as given in par. 360. To serve the piece. S*?!. Eight men are necessary: one chief-of-detachment, one gunner, and six cannoneers. The implements and equipments are arranged as follows : Truck handspikes (iron)...} ^'XTsis^'''''^' ^'^^' '''' ^^^ hooks of Wlieel-chocks (iron) One on each side, on the hurters. Blocks and fall Attached to the crane. The other implements (omitting the wooden handspikes) are the same, and are arranged in the same manner as in par. 3C0. To prepare for pointing the mortar. 3'9'2. In every position of the piece, the plane of fire passes through and includes the axis of the pintle. The position of this axis is determined by suspending over the centre of the pin- 168 13-INCH MORTAR — CENTRE PINTLE — SERVICE. tie a plummet ; this is most readilj'^ done by using a light trestle, about six feet high, with legs far enough apart to reach across the chassis, allowing it to be traversed about a foot in either direction. The highest point of metal at the muzzle is determined in the usual manner. This being marked, serves the same purpose that a front sight does on a gun — the rear sight being the plum- met over the pintle, or one placed in rear of the platform in the plane including the highest point of metal and the object. If the object can be seen from the mortar, establish a plummet ill rear of the platform, in line with the one over the pintle and the object. The trestle over the pintle is then removed. The aiming is accomplished by sighting on the object from the plum- met in rear, and traversing the chassis until the highest point of metal falls on this line. If, as is generally the case, the object is cut off from view by an epaulment, a point must be interpolated on the line from the object to the plummet over the pintle. This is accomplished as explained in par. 343. On the line thus determined, a plummet is suspended in rear of the platform, as before, and the trestle over the pintle removed. The Lorain sight may be used on this mortar. When Dyer's apparatus is used, the direction is given as ex- plained in par, 210. Remark, Owing to the fact that the top-carriage has some lateral play on the chassis, it is well to have the line of metal marked in the usual way, and then, in aiming, bring this line in the plane of sight. To distribute the implements and equipments. 373. The instructor commands : 1. Take equipments. Executed as in par. 362. To sei^ve the piece. 3*74. The piece will, habitually, be in battery while being loaded. It is in battery when the soles of the cheeks are against the hurters. 3'9'5. The instructor commands : 1. IN-BATTERY. Executed as in par. 363, adding, Nos. 1 and 2 will unchock the wheels of the top-carriage. 13-INCH MORIAR — CENTRE PINTLE — SERVICE. 1G9 1. From battery. 376. Executed as in par. 363, except that Nos. 1 and 2 fol- low up the movement and keep the wheel-chocks closely ap- pHed to the wheels. 1. By the numbers^ 2. Load. 3^7. Executed as laid down in par. 364, with the following- exceptions : When the shell is brought up it is placed under the crane, the carrying-bar withdrawn, and the pulley attached to the shell-hooks by No. 4; Nos. 5 and 6 run up the shell, No. 4 steadying it. When sufficiently raised, it is swung over the muzzle, and lowered to its place in the bore as explained in par. 264; No. 4 swings back the crane and keys it to the cheek. All resume their posts. 1. Aim. 378, The gunner places himself in rear of the chassis, and commands : 1. Chassis in-gear, 2. Heave. At the first command. No. 1 unlocks the eccentric of the front wheel; No. 2 embars with his handspike in the eccentric socket of this wheel, and is assisted b}'^ No. 1 ; Nos. 5 and 6 embar in the eccentric sockets of the truck-wheels upon the sides of the chassis. At the second command, the chassis is thrown in gear; No. 1 locks the eccentric of the front wheel, and No. 2 inserts his handspike in the uppermost mortise of this wheel, No. 1 still assisting him. The gunner then, sighting hy the plummet, commands : Muz- zle RIGHT, or Muzzle left. Nos. 1 and 2, applying them- selves to the handspike in the front wheel, give the piece the right direction. If the chassis traverses witli difflcult3% Nos. 1 and 2 embar separatelj% each with a handspike in a mortise on his own side. The direction being given, the gunner commands : 1. Chassis out-of-gear^ 2. Heave. Executed in a manner similar to that of throwing it into gear. All the cannoneers then resume tlieir posts. No. 3 pricks the vent, and then prepares the primer and lan- yard. The elevation is given as explained in par. 365. The gunner commands : Ready, receives the primer from No. 3, inserts it in tiie vent, and goes where he can best observe the effect of the shot. The cannoneers go to the rear as explained mpar, 365. 170 GATLING GUN. 1. Number one {ov the like), 2. Fire. Executed as \npar. 366. The remaining exercises are executed as explained in pars^ 367 and 368. When Dyer's pointing apparatus is used, the gunner, after the chassis is thrown in gear, goes to the instrument on the parapet, sights through it upon the object, notes the degree, returns and causes the piece to be traversed until the pointer on the chassis is at the same degree on the arc of the platform. G-ATLiNG Gun. {Fig. 1, Plate 17.) 379. The Gatling is a machine gun of small calibre, throw- ing lead projectiles. It is used for field service, and also as an auxiliary in the armament of fortifications. For both purposes, it is mounted on a traveling carriage. Two calibres have been adopted, viz.: the 1-inch, which, in addition to solid projectiles, throws also canister ; and the 0.45- inch, which uses the same cartridge as the regulation rifle-mus- ket. The general features of the mechanism are the same for both,, consisting of a number of breech-loading rifled barrels, grouped around and revolving about a common axis, with which they are parallel. The bore of each barrel extends entirely through it, and the breech is chambered to receive a flange, centre-fire,, metallic-case cartridge. The barrels are rigidly attached to a central shaft extending to their rear, and supporting a cylindri- cal breech -casing, which carries within it all the machinery by which the barrels are loaded and fired. A crank upon the right side of this casing is used for operating the machinery. The barrels are discharged successively as they revolve with the shaft. Each revolution of the crank gives one discharge with the 1-inch gun; with the 0.45-inch, three discharges are made by each revolution. The former is capable of firing 150 shots per minute ; the latter, 500 shots. 1-INCH GATLING — SERVICE. 171 Service of the 1-inch G-atling. Description of Piece. Designatiox. Extreme length of piece Length of barrel ^ liCngth of breech-casing Length of feed-case Cartridges in each case Cartridges in each ammunition chest Total number of rounds for each gua G-un (weight) Total weight of gun, implements, carriage and limber., Number of barrels Number of grooves Depth of grooves Twist: one turn in six feet Preponderance Number of horses for each piece Number of horses for each caisson • No. Lbs. Inch 12 472 2592 315 1008 3263 "lio 68.15 33. 21.5 14.5 0..01 The piece is mounted on tiie 3-inch field-ojun carriage. For field service, each piece is accompanied by one caisson. To serve the piece. 3S0. Ten men are necessary : one chief-of-detachment, one gunner, and eight cannoneers. The equipments consist of three cartridge-pouches, which are hung on the knob of the cascable. At the command of the instructor : Take equipments, the gunner steps to the piece and distributes them to Nos. 4, 5, and 7, who carry tliem slung from the left shoulder to the right side. !N'os. 1 and 2, passing around in front of the axle, assist the gun- ner in removing the cover, which is folded and placed on the limber chest. It should never be laid on the ground, as it would be liable to pick up sand and dirt, injurious to the working of the parts. When the piece is unlimbered, the end of the pole, or if with liorses the heads of the lead horses, are six yards from the small end of the trail handspike, the pole pointing in the direction of the piece. Post of cannoneers, piece unlimbered, {Fig. 2, Plate 17.) 381. Tlie gunner is on the left of the trail handspike, nearly 172 1-INCH GATLING — SERVICE. touching; it:, heels on a line witli the end; I^fos. 1 and 2 are ei2:ht- -een inches outside of tl»e wheels, No. 1 on the rig-ht and jS'o. 2 on the left, in line with the rear part of the wheels; Nos. 3 and 4 arc opposite the trail handles, in line with Nos. 1 and 2, No. 3 on the rioht. No. 4 on the left ; No. 5 is five yards to the right of No. 4, in line with Nos. 2 and 4; No. 6 directly hehind the limber chest, and No. 7 two feet behind the left limber- wheel. All face toward the piece. No. 8 attends to the supply of ammunition, and is with the caisson or at tlie ma site sides. } Sometimes caUed mon- > key-wrench. 1 Made of round iron 0.75 [in. in diameter, with a I stout hook at each end ; J length of links, 5 ins. 6 7 2.75 6 5 12 r'nd r'nd r'nd 3.5 3 2 2.25 1.25 Short roller Gun-chock "Wheel-chock Roller-chock Shifting-plank Trace-rope Rlinc-pliHin . .. 156 The machines and their uses will be described with the ma- noeuvres for sea-coast pieces. 41 f. In every case the wooden handspike is required, and to avoid repetition the following general directions for its use are given. Six are the number generally used, and they are in charge of JSTos. 1, 2, 3, 4, 5, and 6. When men on opposite sides of a piece apply themselves to a handspike, the handspike used is that of one of the even num- bers ; the man to whom it belongs is at the smaller end, the corresponding odd number at the butt end; those who assist place themselves inside of these two numbers; the lowest num- bers nearest the ends. When two or more men work at the same end of a handspike, the man to whom it belongs is at the end, and the other men in the ascending order of their numbers from him. When several handspikes are crossed at the muzzle in order to raise or lower it, they are applied in the order of the numbers of the men to whom they belong, those of the highest numbers nearest to the trunnions. The handspikes used in the mechanical manoeuvres are beveled on one side, as these will enter into places or under bodies where square handspikes could not be used. When a handspike rests on a fulcrum, and the weight on one GENERAL DIRECTIONS. 201 «ncl is to be raised by bearing down on the other, the weight should never rest on the beveled side, as the handspike would not then ,i>ive a good hold, and would be liable to split. In this -case the beveled side should be down. But if used for lifting, as when two handspikes are crossed under the breech or chase of a ^un to heave it upward, their ends resting on the ground or plat- form, the beveled side should be up. When two or more men haul together on a rope, the lowest number is next the object of resistance, and tlie remainder next liim in ascending order of their numbers. 418. At the completion ot each movement of a manoeuvre, the men retain the places they are in at its conclusion, ready to proceed to the next movement, resuming their posts only at the command To YOUR POSTS, which is given by the instructor at the end of each manoeuvre. 419. The front, when a piece is unlimbered or dismounted, is the direction in which its muzzle points; when limbered, it is the direction in which the pole points. In the execution of the following manoeuvres, when a piece is put in motion upon rollers, the terms back and forward are applied to the direction of the breech and muzzle respectively. A body moving upon a roller gains twice the distance passed over by the roller. The ground should be level and firm and the implements in good oi-der. Preparatory to manoeuvering, the implements and machines required are taken to the place of exercise. The instructor ex- plains to the detachment their names, uses, and mode of appli- cation. He then commands : 1. Prepare to manoeuvre. 4dO. The men take the implements, repair to their posts, and place them upon the ground in their rear; the handspikes behind N'os. 1, 2, 3. 4, 5, and G perpendicularly to the axis of the piece, on that side of the cannoneer toward the muzzle, the small ends on a line with their toes ; the chocks equally divided, behind and near Nos. 3 and 4; the long rollers near and behind No. 4, and the short rollers, shifting-plank, trace-rope, sling- The cap-squares are removed by Nos. 3 and 4, assisted by Nos. 1 and 2, and placed in rear of their posts, the nuts ou the cap- squares. The instructor commands : 1. Lower the carriage. The cannoneers man the handspike and rope as before. The gunner commands : Heave. The cannoneers haul upon the rope, and the four nearest the mortar leave it in succession, ap- plying themselves to the handspikes as the weight comes upon it, to prevent any unnecessary shock. The cap-squares are re- placed by Nos. 3 and 4 ; N'o. 2 removes the handspike, and the gunner the trace-rope. SIEGE MORTARS. 225 To mount the mortar. 465. The mortar is standing upon its muzzle ; the front of the carriage eighteen inches from it, on the side opposite the vent. The instructor commands : 1. Mount the mortar. The cap-squares are removed by Nos. 3 and 4 and placed, with their nuts, in rear of their posts. The gunner attaches tlie trace- rope to the pipe, and the cannoneers apply themselves to the rope and handspike as described in the preceding paragraph. The gunner commands : Heave; and when tlie weight of the carriage is fairly supported by the rope, Nos. 3 and 4 take their handspikes and, embarring against the manoeuvering bolts, move the bed as may be necessary until the trunnions are in their beds. Assisted by Nos. 1 and 2, they put on the cap-squares. The instructor then commands : 1. Lower the mortar. Nos. 3 and 4, facing to the rear, embar with their handspikes under the cap-squares, and subsequently under the front notches ; the other cannoneers apply themselves at the rope and hand- spike, and the mortar is lowered as described in par. 464. To mount the mortar upon the mortar-wagon. 466. The mortar is on its carriage ; the carriage, on the plat- form or on the giound ; the trail of the mortar-wagon, its stakes and bolster removed, is about two yards from the pipe and per- pendicular thereto. The instructor commands : 1. Eaise the mortar. Executed as prescribed in par. 464, except that the mortar need not be given any particular elevation, and, instead of allowing it to go over until the muzzle strikes the ground, the carriage is poised in nearly a vertical position by N'os. 1, 2, 3, 4, 6, and 6, while Nos. 7 and 8, embarring with handspikes under the stock of the wagon, guide it under the mortar carriage mid- way between and parallel to the cheeks ; Nos. 9 and 10 working at the wheels. The stock is run under the carriage as far as practicable and the wheels chocked front and rear; the long roller is placed on it by the gunner in such position that when the carriage is lowered its point of contact with the roller will be twenty inches from the toes of the shoes ; the moitar is then lowered upon the roller. 15 226 MECHANICAL MANCEUVRES. The instructor commands : 1. KiG THE WINDLASS. The gunner lays the middle of the trace-rope across the rear notches ; ISTos. 1 and 2 pass the ends underneath and around the rear manceuveriiig bolts, and, carrying them to tiie rear, take two turns with them around the windlass. The windlass is manned as explained in par. 450, and is worked at the command Heave from the gunner. As soon as the mortar is in motion, the second long roller is engaged undei* the shoe, by N"os. 3 and 4, twenty inches from the lower roller, measuring from axis to axis. The lower roller will then disengage just as the mortar is balanced on the upper roller. iNTos. 5 and 6 steady the mortar with handspikes. As soon as the lower roller is disengaged, it is taken out by Nos. 3 and 4, who again engage it twenty inches above the other roller. The mortar is drawn back on the last roller until the heels of the shoes abut against the hurters on the rear cross-bar plate. The roller is now chocked in front, and particularly in rear., by Nos. 3 and 4. The instructor commands : 1. LEMffiER UP. Executed as in par. 450. The gunner then secures the lashing-chain. In raising the stock, in limbering and unlimbering, great care must be taken not to raise it so high as to endanger the over- tmniing of the wagon to the rear. The instructor commands : 1. Stow the mortar. No. 4 removes the front roller-chock, and satisfies himself that the rear roller-chock is in place ; iN'os. 5 and 6 embar over the side rails and under the shoes, near the rear notches, to cant the carriage to the front ; Nos. 1 and 2 ease away gently, and permit the carriage to move forward on the roller until the front notches are over the front cross-bar plate. If the car- riage does not move far enough forward on the roller after canting, N"os. 5 and 6 embar over the side rails and under the front notches, and pinch the carriage forward to its place. The roller is then removed from the rear, and the carriage lowered onto the wagon by repeated purchases, the disengaged roller- chocks and bolster being placed by the gunner as f ulcruras on the rear of the wagon. If the mortar is to travel, its carriage is securely lashed to the wagon. SIEGE MORTARS. 227 467. The most convenient way of carrying tlie implement?, is to fit a bed to the mortar-wagon. The bed is made of stout boards about a foot wide ; those for tlie sides are lield in place bj'' rope beckets passed through auger holes in the boards and around the stakes of the wagon ; the end boards fit between cleats nailed to the ends of the side boards; the whole forming a box about seven feet long, with a width equal to the widtli of the wagon. Slots are cut in the side boards for the manoeuver- ing bolts, which project slightly beyond the side rails of the wagon. To dismount the mortar from the wagon, 468. The mortar is unlashed ; the implements, bolster, and stakes of the wagon are removed. The instructor commands : 1. Dismount the mortar. Nos. 5 and 6 embar over the side rails and under the rear notches, using chocks and bolster as fulcrums, and by repeated purchases raise the mortar carriage until a long roller can be placed under it with the points of contact two feet from the toes of the shoes. The instructor then commands : 1. Rig the windlass. The gunner attaches the trace-rope, and the windlass is rigged as explained in par. 450. At the command Heave from the guimer, the mortar is drawn back against the hurters, Nos. 5 and 6 embarring under the shoes and over the side rails, to ease the carriage when it cants to the rear; Nos. 3 and 4 chock the roller front and {especially) rear. The instructor commands : 1. Unlimber. Executed as explained in par. 451. The instructor commands : 1. Lower the mortar. Nos. 1 and 2 slack off" on the rope, and the mortar is eased down the stock. The second long roller is engaged under the front of the carriage as soon as tlie mortar cants to the front, so tliat the distance between the rollers, measuring from axis to axis, shall be twenty inches; the rollers are shifted in this man- .n- tliem through the rope, so that each stitch lies in the division between two strands. This is called a sewed whipping. 4f 9, Splicing is putting the ends of ropes togetlier by open- ing tlie strands and placing them into one anotiier, or by putting the strands of the ends of a rope between those of the bight. A short splice. Unlay the strands for a convenient length ; then take an end in each hand, place them one within the other, ;and draw them close. Hold the end of one rope and the tliree strands which come from the opposite rope fast in the left hand, or if the rope be large, stop them down to it with a rope-yarn. Take the middle strand, which is free, pass it over the strand which is first next to it, then through under the second and out between the second and third from it, then haul it taut. Pass each of the six strands in the same manner; first those of one end and then tliose of the otiier. The same operation may be repeated with each strand, passing each over tiie third strand from it, under the fourth, and through ; or, as is more usual, after the ends have been stuck once, untwist each strand, di- vide the yarns, pass one-half as above described, and cut off the other half. Tliis tapers the splice. A long splice. Unlay the ends of two ropes to a distance three or four times greater than for a short splice, and place them within one another as for a short splice. Unlay one strand for & considerable distance and fill up the interval which it leaves with the opposite strand from the other rope. Twist the ends of these two together, then do the same with two more strands. The two remaining strands are twisted together in the place where they were first crossed. Open the two last-named sti-ands, divide in two, take an overhand knot with the opposite halves, and lead the ends over the next strand and through the second as the whole strands were passed for the short splice. Cut off the other two Imlves. Do the same with the others that are placed together, dividing, knotting, and passing them in the same manner. Before cutting off any of the half strands., the rope should be got well upon a stretch. Sometimes the whole strands are knotted, then divided, and the half strands passed as above described. This splice does not increase the diameter of the rope, and is used for splicing a fall or other rope that runs through blocks or pulle3''S. An eye-splice. Unlay the end of a rope for a short distance and la}'^ the three strands upon the standing part, so as to form an ej^e. Put the first end through the strand next to it. Put the second end over that strand and through the second, and put Ihe remaining end through the third strand on the other side of 234 MACHINES AND APPLIANCES. the rope. Taper them, as in the short splice, by dividing the- strands and sticlving them again. This is used to form a perma- nent loop in the end of a rope. A grommet. Talce a strand Just unlaid from a rope, with all its turns in it, and form a ring of the size j^ou wish by putting the end over the standing part. Then take the long end and carry it twice round the ring in the crevices, following the lay until the ring is complete ; then take an overhand knot with the two ends, divide the yarns, and stick them as in a long splice. Used for a trunnion loop for rolling or sluing a gun. 4 SO. Two half hitches. Pass the end of a rope round the standing part and bring it up through the bight. This is a half hitch. Take it round again in the same manner for two half hitches. A clove hitch is made by passing the end of a rope round a spar,, over, and bringing it under and round behind its standing part, over the spar again and up through its own part. It may then, if necessary, be stopped or hitched to its own part; the only difference between two half hitches and a clove hitch being that one is hitched round its own standing part and the other is hitched round a spar or another rope. Round turn and two half hitches. Take a round turn around the stakes or posts, and secure the end by two half hitches around the standing part. This is very useful in securing the guys of the gin to the stakes. A bowline knot. Take the end of a rope in your right hand and the standing part in your left ; lay the end over the stand- ing part, and with the left hand make a bight of the standing part over it; take the end under the lower standing part up over the cross, and down through the bight. This is very useful in forming a temporary ej^e at the end of a rope. Square knot. Take an overhand knot round a spar; take an end in each hand and cross them on the same side of the stand- ing part upon which they came up; pass one end round the other, and bring it up through the bight. This is sometimes called a reef knot. If the ends are crossed the wrong way, sailors call it a granny knot. A timber hitch. Take the end of a rope lound a spar, lead it under and over the standing part, and pass two or more round turns around its own part ; pass the first turn over the end part instead of thiough the bight, as in a half hitch. Used in secur- ing the ends of the trace-ropes to the manoeuvering bolts. A rolling hitch. Pass the end of a rope round a spar ; take it round the second time, nearer to the standing part; then carry it across the standing part, over and round the spar and up CORDAGE. 235- throiii^h the bight. A strap or a tail block is fastened to a rope by this hitch. Used in sbiftin,i>- the fall from one end of the windlass to the other. (See nipper and screw.) A hlackwall hitch. Form a bight by putting the end of a rope across and under the standing part ; put the hook of a tackle through it, the centre of the bight resting against the back of the hook, and the end jammed in the bight of the hook by the standing part of the rope. A cafs-paw. Make a large bioht in a rope, and spread it open, putting one hand at one part of the bight and the other at the other, and letting the standing part and end come together; turn the bight over from you three times, and a small bight will be formed in each hand ; bring the two small bights together, and put the hook of a tackle through them both. This is very useful in applying a purchase or taclde to the fall of another. A sheet bend (weaver's knot). Pass the end of a rope up through the bight of another, round both parts of the othei-, and under its own part. Tliis does not jam, and is useful in tying two ropes together. Carrick bend. Form a bight in a rope and lay the end across the standing part ; stick the bight of another rope up through the loop thus formed, and carry the end over the end of the first rope, under the standing part, and through the loop formed by its own bight ; stop each end to its own standing part. Fishermari's bend (anchor knot). Take two turns around the gun-slinir or spar with the end of the rope ; hitch the end around the standing part and through both turns, and then pass the end over the second and under the first turn. A sheep shank. Make two long bights in a rope which shall overlay one another; take a half hitch over the end of each bight with the standing part which is next to it. Used to shorten a rope temporarily. A marlinspike hitch. Lay the marlinspike upon the seizing stuff, and bring the end over the standing part so as to form a bight; lay this bight back over the standing part, putting the marlinspike down through the bight, under the standing part, and up through the bight again. Very useful in putting on lashings, &c. Stopping is fastening two parts of a rope together, as for a round seizing, without a crossing or riding. Nipperinq is fastening them by taking turns crosswise between the parts to jam them, and sometimes with a round turn before each cross. These are called racking turns. Pass riders over these and fasten the end. This is a convenient way to secure a. fall while it is being shifted on the windlass. 236 MACHINES AND APPLIANCES. A screw is applied by weaving a light strap through the differ- ent parts of a fall, bringing the two ends together, and screwing the whole up tight by means of a stick or bar passed through the bights. A strap^ or sling^ is formed by knotting or splicing together the ends of a short strand or rope. It is used for hooking tackles into. Pointing. Unlay the end of a rope and stop it ; take out as many yarns as are necessary, and split each yarn in two, and take two parts of different yarns and twist them up taut into nettles; the rest of the yarns are combed down with a knife ; lay half the nettles down on the scraped part, the rest back upou the rope, and pass three turns of twine taut round the part where the nettles separate, and hitch the twine, which is called the warp; lay the nettles backwards and forwards as before, passing the warp each time. The ends may be whipped and snaked with twine, or the nettles hitched over the warp and hauled taut. The upper seizing must be snaked. If the upper part is too weak for pointing, put in a piece of stick. This is an elaborate way of whipping ropes, and requires considerable prac- tice. Frap. To pass a rope around a lashing to keep the turns together. Seizing a rope is connecting the two parts with smaller rope, or spun-yarn. Take a piece of spun-yarn and double it ; pass the bight under the two parts of the rope to be seized ; put both ends through it and haul taut, using a lever applied with the marlinspike hitch ; separate the ends, pass them around the rope in opposite directions until enough turns are taken, hauling each turn taut, and seeing that they lay close and smooth. Cross the seizing by passing the ends in opposite directions be- tween the ropes and around the seizing, and finish with a square knot. A lashing is applied on the same principles. After sufficient turns have been taken, the lashing is /rapped by taking the ends around the turns, hauling them close together, and making the lashing tighter, of course. To pass a shear lashing. Middle the lashing and take a turn round both legs at the cross; pass one end up and the other down, around, and over the cross, until half of the lashing is expended ; then ride both ends back again on their own parts and knot them in the middle ; frap the first and riding turns together on each side with sennit. This will be useful in rigging shears for hoisting guns, when a gin is not available. Any two spars that will support the weight can be used. CORDAGE. 237 To sling a barrel with both heads in, or a box. Lay it on its side; lay a lono: strap under it, spreading the parts; pass one bi;^ht through tlie other, on top of the barrel, and hoolv on to it. If one head of the barrel is out. Stand the barrel up; put one part of a strap under the middle of the bottom; take a half~ hitch over the top with each part, the hitclies exactly opposite to each other and just above tlie upper bilge hoops. Hook on to the bight as before. Tliose hoops applied near the ends of a barrel are the ''c/ime," and those near the centre the "'bilge '* hoops. Table showing the weight which Manila rope in daily use will sustain^ singly and when rove in tackles. 481. Sismj? rope is about one-third stronger. Due allowance has been made for loss of strength by wear and tear. Look for the weight to be raised, or the next larger, in the column lieaded with the number of sheaves in the purchase or tackle. The circumference of the rope required will be found on the same line in tlie left-hand column. CiRCUlkrFEEENCE IN IXCHES. 1.... 1%. 2.... 2h. 2%. 3... 3%. 354. 4.... 4^. 4H- 454. 5.... 5M. 5%. 5?4. 6.... Single. 6^. 6?4. 7.... 540 844 ],215 1,654 2,160 2,734 3,375 4,084 4,860 5,704 6,415 7,594 8,640 9,753 10,935 12,184 13,500 14,884 16,335 17,954 18,252 19,805 21,421 23,100 24,843 32,448 Number of Sheaves in Pukchasb. 1,080 1,688 2.430 3,308 4,320 5,468 6,750 8,168 9,720 11,408 12,830 15,188 17,280 19,516 21,870 24,368 27,000 29,768 32,670 35,908 36,504 39,610 42,842 46,200 49,786 64,896 1,350 2,110 3,038 4,185 5,400 5,835 8,438 10.210 12,150 14,260 16,048 18,985 21,600 24,393 27,338 30,460 33,750 37,210 41.838 44,885 45,630 49,513 53,553 57,750 62,208 81,120 1,485 2,321 3,342 4,549 5,940 6,519 9,282 11,231 13,365 15,686 17,657 20,884 23,760 26,831 30,072 33,506 37,125 40,931 45,922 49,873 50,193 54,465 58,908 63,525 68,418 89,232 6 1,620 2,582 3,645 4,962 6,480 8,202 10,125 12,252 14,580 17,112 19,245 22,782 25,920 29,259 32,705 36,552 40,500 44,652 49,005 53,862 55,756 59,415 64,263 69,300 74,529 97,344 1,755 2,743 3,949 5,376 7,020 8,886 10,969 13,273 15,795 18,538 20,854 24,681 28,080 31,697 35,529 39,598 43,875 48,373 53,089 58,350 60,319 64,367 6.1,618 75,075 80,740 105,456 .238 MACHINES AND APPLIANCES. To ascertain the strain in pounds which a rope will bear witli- out breaking, multiply the square of the circurriference by the tab- ular number. Dbscbiption. Hemp MM. M^ Manila M o Inches. 2.5 to 6 6 to 8 2.5 to 6 6 to 12 "White. 3-strand. 4-strand. 1140 1090 810 760 1330 1260 950 835 Tarbbd. 3-strand. 4-strand 850 825 1000 940 For ropes in daily use^ the unit should be diminished one-third to meet the reduction in strength by wear and exposure. A safe general rule for all ropes is this : One-fourth the square of the circumference gives the breaking weight in tons of 2000 pounds. When using tackles, multiply the weight thus found by one- half the number of sheaves in the blocks. Straps are applied by passing them around the object, putting one bight through the other, and hooking to this ; or, after put- ting it through, winding all the strap around the rope or spar, and hooking to both bights. Preservation in store. Ropes should be placed in the upper stories of buildings, coiled up and labeled ; large ropes on skids, allowing free circulation of air; small ropes hung up to the joists, on pins or hooks. Ropes should not be coiled until per- fectly dry ; they should be uncoiled evei-y year, and stretched out for several days in the dry season. Ropes long in store lose their strength. Blocks, Tackles, &c. {Plates 29 and 30.) 482. Blocks are of two kinds, made and mortised, A made block consists of four parts : the shell, or outside ; the sheave, or wheel on which the rope turns ; the pin, or axle on which the wheel turns; and the strap, either of rope or iron, which encir- cles the whole and keeps it in its place. The sheave is generally strengthened by letting in a piece of iron or brass at the centre, BLOCKS, TACKLES, ETC. 239 called a hush. IN'earl}'^ all heav}'' blocks for ordnance purposes are made with iron shells and brass sHeaves. A mortised block is made of a single block of wood, mortised out to receive a sheave. All blocks are single, double, or threefold, according to the number of sheaves in them. There are blocks that have no sheaves, to wit : a hulVs-eye^ which is a wooden thimble without a sheave, having a hole through the centre and a groove around it; and a dead-eye^ which is a solid block of wood made in a circular form, with a groove round it, and three holes bored through it, for the lan- yards to reeve through. Snatch blocks are single blocks, with a notch cut in one cheek, .just below the sheave, so as to receive the bight of a fall with- out the trouble of reeving and unreeving the whole. They are generally iron-bound, and have a hook at one end. A tail block is a single block, strapped with an eye-splice, and having a long end left by which to make the block fast tempo- rarily to the rigging. This tail is usually selvaged, or else the strands are opened and laid up into sennit, as for a gasket. 483. A tackle is a purchase formed by reeving a rope through two or more blocks, for the purpose of hoisting. A whip is the smallest purchase, and is made by a rope rove through one single block. A gun-tackle purchase is a rope rove through two single blocks .and made fast to the strap of the upper block. The parts of all tackles between the fasts and sheave are called the standing parts; the parts between sheaves are called running parts; and the part which is taken hold of in hoisting is called the fall. A whip upon whip is where the block of one whip is made fast to the fall of another. A luff-tackle purchase is a single and a double block ; the end of the rope being fast to the upper part of the single block, and the fall coming from the double block. A luff tackle upon the fall of another luff tackle is called luff upon luff A watch tackle, or tail tackle, is a luff-tackle purchase, with a hook in the end of the shigle block and a tail to the upper end of the double block. One of these purchases with a short fall is kept on deck, at hand, in merchant vessels, and is used to clap upon standing and running rigging, and to get a strain upon ropes. A runner tackle is a luff applied to a runner, which is a single rope rove through a single block, hooked to a thimble in the eye of a pennant, A single Burton is composed of two single blocks, with a hook in the bight of the running part. Reeve the end of your ropo 240 MACHINES AND APPLIANCES. throug'h the upper block, and make it fast to the strap of the fLy block ; then make fast your hook to the bi_2^ht of the rope, and reeve the other end through the fly block for a fall. The hook is made fast by passing- the bight of the rope through the eye of the hook and over the whole. This is a very qnick-vvorking tackle and a strong purciiase. Used for hoisting entirely. When a very heavy weight is to be raised, the standing parts should be attached to the slings by a fisherman's bend, instead of to the block. The size of blocks is expressed by the length of the shell in inches ; if ropes of unusual size are to be used, it should be spe- cified in making requisitions for blocks. Tackles are also designated by the number of sheaves em- ployed; as, twofold (two single blocks), threefold (double and single block), &c. A mousing is a seizing placed around a hook to prevent it from spreading or unhooking, and should always be applied as fol- lows: Take several turns of yarn or spun-yarn around the point and back of the hook, and frap the ends around all the turns. The bight of a hook is the middle of the bend of the hook part* Useful suggestions. 484. A tackle is said to be *' two blocks " when the entire fall is hauled through, so that the blocks are in contact. To overhaul a tackle is to separate the blocks. This is best done as follows : Hook the upper block firmly, or let one or two men hold it; let one or more men take hold of the lower block and haul, wliile one man lights the fall through the upper block bj' hauling the running part through it. If necessary, let an- other hand light the second part through. Rope should always be stopped up, either with the end or with rope-yarn stops, to prevent it getting into a snarl. When using ropes for hauling, they sliould never be di-agged upon the ground. To stop up a coil of rope with the end. Lay off two or three turns of tiie coil and take a clove hitch around all parts of one side of the coil. Do the same on the other side. If the rope should be rove in a tackle, run' it ^'two blocks" and make the first liitch around the fall between the blocks. Before reeving a rope in a block, the turns should be carefully taken out to prevent twisting when the weight is lifted. This is done by stretching the rope out to its full length and turning it in the opposite direction to that in which it is laid up, until all the stiftness disappears. Blocks should be overhauled very often to see that the sheaves are working properly on the pin and that they work smoothly. If they do not, turn the pin end for end, and rub a little black- BLOCKS, TACKLES, ETC. 241 lead (graphite) on them to lubricate them, also on the sides of the sheaves where they rub a^^ainst the shell. When hoisting with tackles they should never be allowed to twist. If they show a tendency to do so, insert a bar in the block or sling, and use it as a lever to hold it straight. It frequently happens that the men cannot apply their full strength in the direction in wiiich it w^ould be most effective. In such cases hook a single block to some object about two feet above ground and reeve the end of the fall through it, so that the men can add their strength to their weight and more men -can apply themselves. Kever trust the suspension of a weight to holding it by the unaided strength of men. If it is possible to get a turn around any fixed object, even in raising or hauling a weight, it is best to take a turn, as all that is gained is then saved. Always select such blocks that the fall will run freely through them and not ride upon the edges of the y»heaves. If it does, it will be certain to cut. The rope should not quite fill the score or groove on the sheave. In this way excessive friction is avoid- ed. The sailor's maxim is, *' Small ropes and big blocks." The power gained by using tackles is as follows : Two single blocks, or gun tackle — nearly doubled. Luft' tackle (double and single block) — doubled. If the double block is movable — trebled. Two double blocks — power X 3|-. Double and treble blocks — power X 4. Two treble blocks — power X 4J. Whip upon whip, single Burton — trebled. When one tackle is applied to the fall of another, the power obtained is found by multiplying their respective values together, No advantage is gained by using a greater number of sheaves than two treble blocks in one fall. Weight and strength of ' iron chains. m'r of n for ks. ghtof e foot chain. OA O fcX) m'r of n lor ks. ghtof 3 foot chain. .sg.a ^ o o n Dia iro lin o den 0) o £^ Inch. Lbs. Lbs. Lbs. Inch. Lbs. Lbs. Lbs. 0.1875 0.325 2,240 948 0.625 4.217 26,880 10,304 0.25 0.65 4,256 1,680 0.6875 4.833 32,704 12,544 0.3125 0.967 G,720 2,464 0.75 5.75 38,752 15,232 0.375 1.383 9,634 3,584 0.8125 6.687 45,696 17,696 0.4375 1.767 13,216 5.152 0.875 7.5 51,744 20,384 0.5 2.633 17,248 6,720 0.9375 9.333 58,464 23,520 0.5625 3.833 21,728 8,512 1. 10.817 65,632 26,880 IG 242 MACHINES AND APPLIANCES. The Gin. {Plate 31.) 485. A gill is a tripod formed of three poles. Two of these poles, called legs, are joined togetlier by braces of wood or iron, and contain between them the windlass. The third pole is called the pry-pole, and is joined to the legs, at the top, by a bolt. This bolt supports a clevis, to which the upper block of the tackle is hooked. The windlass is worked by two handspikes fitting into brass sockets, one at each extremity of the windlass ; the operation of the handspike is made continuous by the action of a pawl at- tached to the socket on the ratchet of the windlass. To prevent the legs and pry-pole from sinking into the ground, or injuring the pavement of casemates, stout pieces of wood, called shoes, are placed under them. The hoisting apparatus consists of two blocks, through which the fall is rove. The fall is wound two or more times around the windlass. There are three kinds of gins used for artillery purposes : the siege, the garrison, and the casemate. The last two differ from each other only in height ; the first differs from the others in construction and size. Piper's gin is an improved modification of the siege gin. When the gin is put together and raised, that part included between the legs and pry-pole is called the inside, the outside being the part without the legs; the right corresponding to the right hand of a man standing at the middle and outside of the windlass, facing towards it, the left corresponding to his left hand. 4:$6. The detachment is composed of one chief, one gunner, and ten cannoneers. The odd numbers are placed on the right and the even numbers on the left side of the gin, all facing in- wards ; N"os. 1 and 2 opposite and one yard outside of the foot of the pry-pole ; l^o. 9 outside of and near the foot of the right leg ; 'No. 10 outside of and near the foot of the left leg; ISTos. 3, 5, and 7 are between N"os. 1 and 9, dressing on them and dividing the intervening space into equal distances; Nos. 4, 6, and 8 oc- cupy similar positions with respect to ITos. 2 and 10. In assem- bling the gin, the gunner and Nos. 1 and 2 bring up the pry-pole ; Xos. 3, 5, and 7 the right leg, and Nos. 4, 6, and 8 the left leg; ]!^os. 9 and 10, the windlass. The gunner superintends putting together the head, and the chief-of-detachment the placing of the windlass. The braces are brought up and adjusted to their places by N'os. 5, 6, 7, and 8. The gunner, assisted by the most expert cannoneers, reeves THE GIN. 243 the fall, slings the piece, and attends to all knottings and lash- in,ij:s. In working the windlass, Nos. 1 and 2 hold on to the fall and take up the slack ; Xos. 7 and 9 work at the right, and Nos. 8 and 10 at the left handspike, i^os. 7 and 8 being next the wind- lass. All, except the old-pattern siege gin, are put together and hoisted by raising the head and bringing up the foot of the pry- pole towards the feet of the legs. 487. The siege gin (old pattern) is put together with the out- side of the legs and windlass downwards and the pry-pole rest- ing on the top. {Fig. 1, Plate 32.) It has no clevis, as other gins, and, instead of an upper block, two sheaves are inserted •between the legs and secured by the bolt holding together the legs. The head of the pry-pole is terminated by a flat piece of iron, which fits between the heads of the legs above the sheaves, -and is secured by another bolt. This gin further differs from others in having three wooden braces instead of two of iron. It has the disadvantage of being exceedingly ill-contrived and unhandy. To put the siege gin {old pattern) together, 488. The different parts of the gin having been brought to the place designated, the instructor commands : 1. Assemble the gin. This is executed as indicated in pars. 486 and 487. The gin being together and lying on the ground, the instruct- or commands: 1. Keeve the fall. iSTos. 1 and 2 raise the pry-pole until it clears the sheaves. The gunner, receiving from Nos. 3 and 4 one end of the faU, passes it through the left sheave from beloW and hands it back' to them. They pass it through the sheave of the single pulley, (hooked for convenience on the middle brace,) and return it to the gunner, who passes it through the right sheave from below, and gives it to '^o. 3, by whom it is secured by wrapping it around the middle brace. If the gin has been raised, the instructor gives the same -command, when the gunner, mounting upon the upper brace, receives from Nos. 3 and 4 one end of the fall, which he passes over the left sheave from without to within. The fall is then j-eeved in the manner prescribed. To raise the gin. The instructor commands : 1. Kaise the aiN. Nos. 1 and 2 take hold of the handle of the pry-pole ; Nos. 9 244 MACHINES AND APPLIANCES. and 10 each hold down the foot of a le^ to prevent it from slip- pin^^ ; IS^os. 3 and 4 lift at the head, and Nos. 5, 6, 7, and 8 ap- ply themselves at the legs on their respective sides. The gunner commands: Heave; tlie gin is raised ; Nos. 1 and 2 caVry out the foot of the pry-pole about twelve feet from the windlass and place under it a shoe. A shoe is likewise placed under each leg^ To move the gin when raised. The instructor wishing to move the gin a short distance, indi- cates the direction and commands : 1. Move the gin^ 2. Mabch^ !N"os. 1 and 2 apply themselves at the handle of the pry-pole;. iJ^os. 9 and 10 each place a handspike under the windlass fi-ora without, and near the legs; Nos. 7 and 8 assist to lift at these handspikes from within ; at the command MARCH, all move in the direction indicated. To lower the gin. The gin is lowered in a similar manner, but by inverse means to that prescribed for raising it. Nos. 1 and 2 raise the pry-pole and assist in easing the gin to the ground, the outside down- wards. 489. The following are the kinds, dimensions, weights, and strengths of ropes usually required for the ditterent kinds of gins : Designation. 5 U 3 6 to © Weight. Remarks. i o o o ft ® o O Gin fall (siege.) G-in fall (garrison and casemate.) Gun-sling (siege.).... Trace-rope Lashing-line Inch. 4.25 6 6 3.25 1.75 Feet. 75 120 26 30 10 100 Lb. Oz. 5 4 10 6 10 6 3 1 11 Lb. Oz. 67 8 208 44 9 15 5 1 2 11 Lbs. 8,064 16,128 16,128 4,760 1,371 Hemp. Hemp. An eye at one end, served with leath- er. Hemp. Manila. Hemp. Hemp. Marline THE GIN. 245 To mount a siege gun. 490. It is imnQaterial upon which side of the piece the le.a:s ot the gill are placed, but, for uniformity, they are generally placed on the right. The gun is suspended either by a sling or by a bail ; the latter is preferable. It consists of a stout piece of iron {Fig. 2, Plate 32), passing like a handle over the piece and fitting against the ends of tiie trunnions, to which it is fast- ened by iron bolts passing through the ends of the bail into holes bored for the purpose; one in the end of each trunnion. A clevis, attached to tiie middle of the bail, gives a place for hooking the lower block of the tackle. The gin being raised and placed with its tackle directly over the trunnions, and the foot of the pry-pole about twelve feet from the lower brace, the instructor commands : 1. Sling the piece. No. 1 puts a handspike in the bore, small end foremost; I^o. 2 passes the eye or loop end of the sling around the knob of the cascable ; No. 1 passes the other end under the handspike in tlie bore, and hands it to No. 2, who draws it through the loop; the gunner fastens it either by a knot or with a lashing-rope, and tiien hooks the single pulley to the sling just in rear of the trun- nions, fastening the standing end of the fall to the sling near the same place ; Nos. 1 and 2 pass the running end of the fall from the outside under the windlass, and take three turns with it around the left of the windlass, and hold on by the running end or slack. No. 1 being nearest the windlass; the gunner applies himself to the handspike in the bore to steady the piece ; Nos. 7, 8, 9, and 10 apply themselves at the windlass handspikes. All ' being in readiness, the instructor commands : 1. Hoist away. The windlass is worked until the piece is high enough to admit the carriage under it. The instructor then commands : 1. Halt, 2. Eun up the carriage. All the men, except Nos. 1 and 2, bring up the carriage, as explained in par, 435, placing the trunnion beds directly under the trunnions. The instructor then commands : 1. Slack off. Nos. 1 and 2 slack of the fall slowly ; the gunner steadies the ;jpiece by means of the handspike in the bore, and the piece is 246 MACHINES AND APPLIANCES. lowered into its position in tlie trunnion or traveling beds; ]N"os- 3 and 4 put on tiie cap-squares and key them. Note. — ^Wiien the bail is used, it is attached by the same num- bers as for the sling. If it is noc convenient to sling tlie piece in the manner prescribed, it may be slung by a rope passed around each trunnion, and the ends fastened together on top of the piece ; or trunnion rings may be used. Hook the pulley to this sling or to the trunnion rings; bear down with one or two men on the handspike in the bore to balance the piece, and when it is raised sufficiently high run the carriage under it, and place a handspike in the trunnion beds and a block on the stock. (For casemate or barbette carriages, upon scaffolds built of blocks under the breech and chase.) Lower the gun, the trunnions di- rectly over the trunnion beds, until the piece rests on the block and on the liandspike. Remove the sling or rings from the trunnions and rim the carriage, with the gun on it, back until the head of the cheeks are in rear of a perpendicular let-fall from the head of the gin. Pass the sling around the chase, hook the pulley to it, and work the gin until the weight no longer bears on the handspike in the trunnion beds; remove the handspilce, and lower the trunnions to their places; bear down on the muz- zle, and remove the block from under the breech. To dismount a siege gun. 491. The gin is placed in the same position with reference to the piece as prescribed for mounting it. The instructor com- mands : 1. Sling the piece. The cap-squares are removed, the piece is slung, and the run- ning end of the fall passed around the windlass as prescribed for mounting it. The commands Hoist away^ Halt, Bun out the carriage^ and Slack off are then given and executed in the manner already prescribed. To sling and hoist a siege mortar mounted on its carriage. 492. A gun-sling or a sling-chain is used. In either case, the middle of it is passed under the front notches; the ends car- ried up, and, crossing over tiie top of the mortar, are passed un- der the rear notches. The gin is erected over the mortar and the lower block of the tackle hooked into the sling where it crosses the top of the mortar. The mortar is raised and lowered upon a wagon in the manner prescribed for a gun. THE GIN. 247 To sliift the fall. 493. As the turas gain once the diameter of the fall at each revolution of the windlass, they will, when the weight has been raised a considerable height, come against the opposite leg. The instructor then commands : 1. Halt, 2. Shift the fall. The gunner mounts to a position where he can reach the run- ning part of the fall, and firmly applies a nipper to two of the parts as explained in par. 480. The instructor then commands : Ease away. N'os. 1 and 2 slack off and shift the turns on the windlass to the opposite end ; they then tighten up the fall, the nipping is removed by the gunner, and the manoeuvre is re- sumed. Piper's gin, 494. In this gin, the windlass is attached by placing it in windlass seats of peculiar construction, and is secured in posi- tion by keepers attach(^d to the legs. The keepers are placed under the axles of the windlass. Two stay-chains connect the prj^-pole and legs at the upper brace-bands, and prevent them from spreading. They also serve to connect the parts for trans- portation. Two braces (upper and lower) connect and secure the legs when the gin is put together, and serve to distinguish the right from the left leg — the long brace being permanently attached to the right and the short brace to the left les:. The clevis and clevis bolt are attached to the head of the pry-pole with keys which secui-e the clevis bolt when the gin is assem- bled ; double and single blocks, with fall, are used. This gin was designed by the late Captain J. W. Piper, fifth artillery. Length of legs , 13 feet 8 inches. Length of pry-pole 13 feet 8 inches. "Weight of gin.,..., 365 pounds. Weight of windlass 88 pounds. Weight of block and fall 100 pounds. Weight of ball and dowels.. 41 pounds. The parts are estimated to be sufficiently strong to bear a weight of 5000 pounds. The advantages of this gin are, its superior ligiitness and portabilit}', and its great facility of being assembled, taken apart, packed up, and transported. The different parts having been brought to the place designa- ted, the gin is put together, raised, lowered, and taken apart by^^ the following commands from the instructor: ASSEMBLE THE GIN. Nos. 1 and 2 place in position the pr3-pole ; iSTos. 3 and 5 place in position the right, and IsTos. 4 and 6 tlie left leg ; the gunner, assisted b}'^ Nos. 3 and 4, attaches the clevis and clevis 248 MACHINES AND APPLIANCES. bolt, assembles the head of the ghi, and hooks on the block and fall ; ISTos. 5 and 6 attach the braces. The gin, hi this position, is lying extended upon the ground, with the inside downwards. The instructor commands : Eaisb the gin. N"os. 9 and 10 hold down the feet of the legs to prevent them from slipping ; ^os. 1 and 2 push up, applying themselves at the handle of the pry-pole. The other numbers apply them- selves as in par. 488. The gunner commands : Heave. The gin is raised and the pr3^-pole brought up to within about twelve feet from the legs; N'os. 3 and 4 attach the stay-chains on their respective sides, and ISTos. 9 and 10 put in the windlass. To move the gin when raised. Executed as explained in par. 488. To lower the gin. The gin is lowered in a similar manner, but by inverse means to that prescribed for raising it. The stay-chains are unhooked and windlass removed before lowering. To take the gin apart. The gin is taken apart in a similar manner, but by inverse means to that prescribed for putting it together, and is stowed for transportation by lashing together the legs, pry-pole, and windlass vyith tiie stay-chains. The application of this gin to the mechanical manoeuvres of siege ordnance is similar to that prescribed for the siege gin (old pattern). GrARKISON AND CaSEMATE GiNS. 495. The garrison and casemate gins differ from the siege gin in iiaving two cross-bars of iron instead of the three wooden cross-bars, and in having the pry-pole inserted between the legs, which are kept together by the clevis bolt. The upper block (generally treble) is hooked to the clevis. The casemate gin is made shorter than the garrison gin, so that it may be hoisted in casemates. With the guns now usually mounted in casemates, it is essential to use a bail for slinging, in GARRISON AND CASEMATE GINS. 249 order to sain the necessary distance from the head of the gin for the working of the tackle. The gin is put together across the piece, or on the ground near it, and raised by moving up tiie legs and pr57--pole towards each other as explained in preceding paragraph. The pry-pole has Wood and Iron. Iron. Wood. '2, wooden. ( 2, iron. Iron. Wooden. Main tackle, leading Muzzle tackle 1 2 ""i Muzzle tackle, leading.. Guy taclde, leading 2 2 1 2 2 Preventer tackle Fore-guy tackle 1 Fore-guy tackle, leading Luff tackle 1 1 1 1 Girtline Two capstans^ wooden ; four stakes for securing capstan, 8 feet long, 5 inches diameter; eight stakes for securhig capstan, J. y 290 MACHINES AND APPLIANCES. 6 feet fong, 5 inches diameter; two skids ^ yellow pine, 18 feet long by 12 by 15 inches ; fifteen blocks^ yellow pine, assorted (four sizes); stakes for securing sill, 8 feet long, 5 inches diameter. To raise a lo-inch gun. 549. The derrick is put together on top of the rampart (or other place to which the gun is to be raised) ; the sill is about five feet from the edge of the wall ; the main-tackle upper block is lashed to the cap near one leg, and the, muzzle-tackle upper block near the other leg. The ends of the guys {Fig. 3, Plate 51) are hitched to the ends of the cap ; the middle laid aci'oss the legs, and a half hitch taken over each end, thus doubling them ; a stout thimble is placed in the bight of each, into which the guy tackles are hooked. Secure hold-fasts must be obtained for the guys; to these the guy straps are attached, and in the bight of each a stout thimble is placed, into which the guy tackle is hooked. One end of the fore guy is attached to the middle of the cap b}'^ a round turn and two half hitches, the end being securely stoppered to the guy. A luff-tackle purchase is applied to the fore guy and its hold- fast, and by means of this the derrick is raised to a vertical posi- tion . The sill is firmly secured, with stakes or by bracing with skids, against some fixed object. The girtline is attached to the cap by a strap, and having been raised with the derrick, a man is sent up by it, who, by r,he same means, receives the leading blocks, which he secures to the cap by means of straps. The main-tackle fall is next rove through the blocks, and the lower block lashed to the gun 2 feet 6 inches in rear of the axis of the trunnions. The muzzle-tackle fall is rove, and the lower block lashed 3 feet in front of the axis of the trunnions. These blocks are each lashed to the gun by seven turns with the lower- block lashing, the lashing being trapped on each side of #the blocks with its ends. "^ Two snatch blocks are attached to the sill, one near the foot of each leg, by strong straps. These straps should be laid on the ground under the sill previous to raising the derrick, and if the ground is gravelly thej'' should be protected from chafing by canvas laid under them. Through these snatch blocks the main and muzzle tackle falls are severally led, each to one of the capstans. The capstans are manned by sixteen men each. A strain is brought upon the falls, and the guy tackles hauled upon until ^ DERRICKS. 291 Ihe head of the derrick is almost vertically over the edge of the wall. The capstans are worked and the gun is hoisted, care being observed to work the capstans so as to keep the piece in a hori- zontal position. One or more shifting-planks are let down by ropes against the side of the wall to prevent the gun from chafing against it and to ease it over the coping. When the gun reaches the top of the coping, preventer tackles are hooked to straps around the breech and muzzle. When the piece is suflSciently high, the guy luft' tackles are hauled upon and the piece landed on cribs or blocks. The preventer tackles are likewise used to assist in bringing in the piece and landing it in a proper position. If it is desiired to place the gun on the cradle, the falls are slacked oflf and the sill of the derrick moved far enough back to admit the cradle. The gun is again raised and landed in its bed on the cradle. The derrick should not be allowed to assume an inclination of less than four upon one. To lower a 15-inch gun, 550. The piece is brought to the edge of the wall on the cradle; the derrick is erected over it; the gun-sling and the tackling attached, all in the manner explained for iioisting; the capstans are worked ; the piece lifted and eased to near the edge of the wall bj'' the preventer tackles. The cap of the derrick having been placed directly over the piece, the strain will in- crease its inclination sufficiently to allow the gun to be eased to the edge of the wall. In this position the piece is allowed to rest on blocks or skids, the cradle is removed, and the sill of the derrick moved up close to the gun. The gun is then hoisted, eased over the edge, and lowered to the foot of the wall. ^'he derrick is dismantled in the inverse order in which it was put up. J^ote. — One capstan, if powerful enough, is sufficient for low- ering or hoisting the gun, in which case the lower block is lashed to the piece at the centre of gravity. The lashing is executed as before explained. The capstan usually issued to artillery posts is, however, not sufficiently powerful, and it will invariably require two of them. Care must be taken to keep the guys hauled upon so that the cap and sill remain always parallel to each other; the derrick is thus prevented from twisting. By omitting tlie cap and then lashing the heads of the spars 292 MACHINES AND APPLIANCES. together with shear lashing, the derrick may be used as shears^ In this case, only the main tackle can be used. When spars can be procured of sufficient length to construct shears high enough, it is best to place the shears at the foot of the wall instead of on top. The shears should be not less than 20 feet higher than the wall. This method permits the piece ta be raised and eased over to the terre-plein with less inclination^ and consequently less strain upon the legs of the shears and on the guys. %xt imxtHt. OAEE AND PRESERVATION OF ARTILLERY MATERIAL. 551. All cannon and other artillery material are either man- ufactured or purchased by the Ordnance Department and turned over to the artillery arm for use. It is the duty of the artillery to care for and preserve such property, and to return to the Ordnance Department for repairs ^uch as may require it. Officers in charge of permanent works will keep, as far as pos- sible, the armament complete and in serviceable condition, and will also keep on hand a proper quantity of ammunition and other supplies. 55S. A book is furnished to each post for the " record of artil- lery " and ''''record ofjlring.^'' In the front of this book are printed instructions fully explaining how it is to be kept. Under appro- j)riate headings, in the part set aside for record of artillery, each gun is described by its number and marks; when received and where from; whether mounted or dismounted; if mounted, in what part of the work, stating its platform number. The result of each inspection, made as hereinafter described, will be entered for each piece in tliis part of the book. In the portion of the book devoted to record of firing, each piece has a separate page, which, when filled, is carried on to another. lEach shot fired is duly recorded as to date of fire, kind and weight of projectile, kind and quantity of powder, elevation, time of flight, range, &c. When a piece is transferred from one post to another a complete record is sent with it, and the pre- vious number of fires is entered in the book at the last post, so that the firing may not go beyond the limit prescribed as the endurance of the piece; this has been fixed at one thousand service rounds for cast-iron cannon. 553. Marks. All cannon are required to be marked with the weight in pounds, the number of the piece, the initials of the inspector's name, the initials or name of the foundry, and the j^ear of fabrication. All pieces manufactured since 1861 have ihese marks on the face ; those of previous date have them dis- (293) 294 CARE AND PRESERVATION OP tributed on the ends of the trunnions, the face, the breech, an^ the top. The numbers for each kind and calibre at each foundry are in separate series. Cannon that have been inspected and condemned are marlied on the face X C. 554. Ordnance-sergeant. The ordnance-sergeant of a post has, under the commanding oflBicer, immediate charge of all the artillery material at the post. It is his special duty to see to its care and preservation, and to keep the books and records relat- ing thereto. He takes an account of receipts and expenditures, makes a memorandum of all breakages and damages, and keeps the commanding officer informed as to the condition of the armament of the post and the extent of the supplies. 555. Preservation of artillery. Cast-iron cannon, whether mounted or dismounted, should be lacquered once a year. The lacquer used is coal-tar of the best quality, mixed with sufficient spirits of turpentine to make it work freely with a paint brush.. It should be applied only in warm weather. The muzzle of the piece should always be depressed so that water may not stand in the bore, the tompion kept in, and the vent closed. At least once a month, especially after a rainy period, the bore should be sponged dry and oiled by passing: down it a sponge saturated with sperm oil ; especial attention in this respect should be given to rifled guns. In cold weather a lit- tle kerosene oil is mixed with the sperm. The vent at the same time is examined and oiled, and if the piece is not in use, stopped with putty or a plug of soft wood. When the piece is mounted, the trunnions and trunnion beds are kept from rusting by pour- ing a small quantity of the same oil into the beds and elevating and depressing it several times. Once a month the carriage should be traversed so as to change its place of rest on the traverse circle. At the same time tiie pintle and axle journals are oiled with sperm oil, and pieces with hydraulic oi- pneumatic butters run from battery and the pistons cleaned and oiled. If the pistons are found rusted, the rust is removed with fine emery-cloth, and the surface polished smooth with rotten-stone and oil. Such pieces ought always to be kept in batteiy and the air holes in the cylinder heads carefully closed wi'h the plugs. The axles of the truok-wheels are cleaned and cared for in the same manner as the pistons. Elevating screws, when not in use, are kept in the store-house, and are cleaned and oiled in the same way. Guns, especially rifled pieces, in batteries exposed to blow- ing sand, should, in addition to the tompion, be provided with ARTILLERY MATERIAL. 295 canvas hoods placed over the muzzle. When firing, this is a useful precaution. Cannon not mounted should be placed together, according to Ivind and calibre, on slcids of stone, iron, or wood laid on hard ground, well rammed and covered with a layer of cinders or gravel to prevent vegetation. The pieces should rest on the skids in such a manner as to be rolled over when necessary for lacquer- ing, the muzzle depiessed and in such position as to be readily got at with tlie sponge. Tiie place selected should be free from shade of either buildings or trees. Siege mortars may be placed on their muzzles, resting on thiclc planks or pavement. 556. Carriages. Iron carriages should be painted once a year, and this in dry, warm weather. The best paint for preservation of iron is red-lead, but this being comparatively expensive, the kind generally used is oriental red paint. It is supplied ready mixed, and is applied in the usual manner of painting. If it should re- quire thinning down, this i.; effected by adding turpentine and linseed oil, the latter either boiled or raw. Before painting, all blisters, rust, or accumnlation of old paint should be removed with a scraper. The top of the chassis rails should neitlier be painted nor oiled, but kept clean by dry scrap- ing. All iron handspikes, elevating-bars, and similar imple- ments are painted black, using for this purpose comuion black paint. Heads of bolts and edges of rails may likewise be painted black. Tile damp location of most artillery posts is particularly favor- able to the rapid decay of material. Rust gradually eats away iron parts of carriages and machines. These defects are fre- quently hidden by repeated coats of paint or lacquei-, making them extremely liable to lead to accident or disaster. Such partis should be carefully examined by means of punches and ham- mers, and no such material be suffered to remain where it is dangerous. The wooden parts of gun carriages and machines frequently become dry-rotted, while the exterior, covered v/i'di pain::, con- tinues a shell apparently quite sound. Sounding such parts with a hammer, and searching into craclof the movable sockets embraces the C5dinder, so that when the INSPECTIOX OF CANNON. 301 wed^e is moved forward the sockets aie forced outwards, and^ when moved backward^! the sockets are withdrawn. The sides of the wedge incline 0.35 inch in a length of 22 inclies, so that by pusliing tli(» slide in the thirty-fifth pai-c of this distance, tiie dis- tance iietween the two soclcets is increased 0.01 inch. A square sliding rod (c) is connected with the wedge, and runs through the whole length of the tube, projecting a few inches beyond the outer end. This rod is in three parts, like the staff, and, like them, connects by screws. The sections of the rod aie prevented from falling out of their proper section of the staff by pins. When screwing the joints of the staff together, if the ends of the rod are pressed up to each other they become connected hy the same motion. The staff is graduated into inches and quarters, so that the distance of the point from the muzzle of the piece may always be known. The handle {Fig. 2, Plate 54) is made to fit over the outer end of the staff, and to connect with the sliding rod by a screw hav- ing a milled head at the outer extremity of the liandle. It may be used on either joint, as most convenient for the length of the bore. The socket of the handle slips over the end of the staff made smaller for the purpose, and has a slot in it, allowing the staff to be seen through it. A scale on one side of the slot is graduated to show the distance that the rod moves to throw the points 0.01 apart. That part of the handle containing the slot and scale is sepa- rated from the other part, but is made to fit closely over it. On one side there is a mill-headed screw for clamping the parts to- gether. Seen through the slot is a small plate of silver inst^rted in the staff, and a fine mark upon it to show the place of the zero when the points are adjusted. The zero mark on the scale is made to correspond with it by means of the screw just mentioned. A set of adjusting rings belongs to the instrument — one for each calibre — reamed out to the exact minimum diameter of the bore. To adjust the gauge for any calibre, the handle is loosened by means of the clamp screw, the proper measuring points are screwed in, the adjusting ring placed over them, and the slider pushed out until all the points touch the inner circumference. The zero of the scale is then made to coincide with the mark on the tube, and the handle clamped; the instrument is then ready for use. The arms of the T-rest {Fig. 3, Plate 54) are adjusted for the particular calibre. It is placed in the muzzle to keep the insti-u- ment in tiie axis of the piece. A centre line, starting from the ^G2 INSPECTION OF CANNON. centre of one of the permanent sockets, is marked on the stafl' throughout its length. In joining the sections together care must be taken to secure coincidence of this centre line. When the gauge is in the bore the centre line should be uppermost; the movable points are then horizontal, and measure the diam- eter of the bore only in a horizontal plane. To make a thorough measurement in every direction, the piece should be on skids, and then by rolling it over different elements of the bore will be brought uppermost, and can be measured in succession. When the piece cannot be rolled over, and it is desirable to obtain measurements all round at any part of the bore, the gauge may be inserted with the movable points in the direction in which it is required to make the measurement. The centre line of the staff will indicate the direction of the measuring points. To ascertain thoroughly the condition of the bore, measure- ments should be made at intervals of 0.25 inch in tlie part occu- pied by the charge and shot; at intervals of one inch in the rest of the bore in rear of the trunnions, and at about one calibre intervals from the trunnions to the muzzle. In the original inspection of the piece, no variation greater than 0.03 inch beyond the true dimensions was allowed; there- fore anything exceeding this is an enlargement caused by serv- ice. The scale upon the handle of the instrument is marked to correspond to hundredths of an inch of movement of the meas- uring points. The divisions are numbered both wa3'^s from the zero. Those towards the handle indicate excess of diameter; those in the other direction indicate deficiencj^ Rifled pieces are measured across from the lands — not from the grooves. In doing this, a special instrument is required for guiding the meas- uring points so that they will follow the lands as they proceed along the bore. Tiie hexagonal hole {Fig. 4) in the centre is fitted on to that portion of the end of one of the measuring points which is similarly shaped. Two small arms on either side of the guide-piece face each other, and can be moved toward or from each other by means of sliding plates to which they are attached. For this adjustment, finely-divided scales are marked on the sliding plates. When in the bore the two small arms rest in two contiguous grooves, and embrace between them the land which the measuring point is forced to follow. To prevent obstructing the motion of the measuring point when it is shoved out by the slider, the arms rest upon light springs, which are simply compressed during the measurement. The hexagonal socket is made to turn within the rest of the guide-piece to allow the necessary freedom to the arms. Before and after each set of measurements, the rings must be -applied to the points and the instrument adjusted. IMPRESSIONS OF THE BORE. 303 Instruments for taking impressions. 562. The machine {Fig. 1, Plate 55) for taking the interior impression of the vent consists of a wooden head (a), one-half the length of which is cylindrical and the other half rounded off to the shape of the bottom of the bore. The diameter of the head is rather smaller than the bore. A staff (6), flat on the upper side and rounded on its under side to fit the curve of the bore, is mortised into tlie cylindrical part of the head so that tlie rounded side will be coincident with the circumference. A mor- tise (c) is cut through the head, extending several inches in rear and front of the position of the vent. Into this mortise a loose block is fitted, capable of free upward and downward motion. The top of the block is pierced with holes to secure the compo- sition spread over its surface. This movable piece rests on a wedge {d) attached to a flat rod running through a slot in the head. To prevent this rod and the wedge from coming entirely out of tlie head, a slot, about four inches long, is cut in it, through which passes a pin (e) attached to the staff'. To use the Instrument, withdraw the rod as far as the slot will permit ; this allows the block to drop below the surface of the head, and protects the composition which has been spread on it; push the head to the bottom of the chamber, and arrange the position of the staff" so that the movable piece will cover the vent; then press the end of the rod home. This motion will throw out the block with the composition, and a distinct impres- sion of the vent and of fire-cracks (should there be any) will be left upon its surface ; draw the rod back as far as the slot will allow, and withdraw the instrument; the impression, being pro- tected thereby, will come out uninjured. Gutta-percha impressions of a poi-tion of the bore of a gun can be taken hy means of wooden blocks or wedges. For this pur- pose use two blocks {a 6, Fig. 2, Plate 55), one about two- thirds the length of the other, the longer block to carry the gutta-percha for the impression, the shorter one to be driven as the wedge, each block with a staff" or handle longer than the bore of the gun, so as to enable the operator at the muzzle to place the blocks in any desired position in the bore; also for driving the wedge and withdrawing the blocks. These blocks are so shaped that when in one position they form an imperfect cylinder, whose diameter is less than that of the boi-e, thus en- abling the longer block to carry the gutta-percha to the required place in the bore ; then, by driving the wedge, the diameter of this cjdinder is increased nearly to that of the bore, the gutta- percha is caught between the surface of the bore and its carry- 304 IMPRESSIONS OF THE BORE. in^ block, and is thus forced by the driven wedge to take note of whatever it finds tiiere. To take an impression, the gnn sliould be tlioronglily washed out and then oiled witli an oiled sponge; the gntra-percha is softened by means of hot water, jnst under the boiling point, to the required consistency, about that of putty; is then placed on the block, which is well oiled (sperm oil is the best), and worked and kneaded with oil until it is spread over the required portion of the block ; the blocks are well oiled, particularly the surfaces which come in contact ; the two blocks are put together at the muzzle so as to enable the carrying block to carr}' the gutta-percha to the desired place ; when both blocks together are pushed into the bore, the distance may be marked on the handle of the carrying block ; tlie carrying block is then held steady by its handle, while the wedge block is driven in by sev- eral blows of a sledge on the end of its handle ; from two to five miinites is sufiicient time to allow it to set. The wedge- block is withdrawn first, and the cari-j^ing block with tlie impres- sion afterwards. To withdraw the wedge block, run an iron pin through the handle near the end, and strike against that with a sledge until it starts, when it is easily withdrawn ; the carrying block will generally fall or release itself by its own weight, bringing the impression with it. If the impression ia taken anywhere in the upper half of the bore, and for this reason, and also that it is easier to work the blocks, it is always better to tur-n the gun over, so as to take the impression above the block. When tiiis cannot be done, and an impression is wanted from the bottom of the bore, a small block or rider is^ pushed in at the same time as tlie canying block, so as to keep the gutta-percha from touching the surface of the bore while being pushed into place. Afterwards the rider block is with- drawn, the wedge driven, and after the wedge is withdrawn the rider block is pushed back close to the c irrying block, and acts as a fulcrum by which the impression is raised free from the bore, when both are withdrawn together. In taking an impres- sion on the side, it is better to push in the blocks as if the im- pression was above, and then to turn the blocks to the place. Unless the block under the gutta-percha is well oiled, some diffi- culty may be experienced in releasing the impression from the block. The carrying block should have a slight raised edge on each side of the upper surface to prevent the gutta-percha from spreading out too much when undergoing the pressure from the wedge, and also to protect it when turning tlie blocks for side impressions. In cases where there is any doubt as to the state of the bore IMPRESSIONS OF THE BORE. 305 of rifled guns, impressions should be taken of the whole leno^th with ,:^ntta-percha, and for doino^ this the blocks just described should be long enouo;h to reach from the bottom of the bore to a foot or more bej'ond the muzzle. They are, in fact, scantling rounded off and made wedge-shape. A convenient size to obtain the gutta-percha, is in slabs twenty inciies long, live wide, and five-eighths thick. Each slab will make ordinarily two or three impressions. It can be used over and ovei- again, and need never be thrown away if a little fresh material be added occasionally to prevent it from becoming brit- tle. It must be kept free from dust or grit, and should be pre- served in water when not in use. As a proper set of instruments is rarely or never to be obtained at artillery posts, a substitute for taking impressions with the wax composition may be made by using a block of wood about a foot in length, one side of which is rounded off so as to have the curvature of the bore ; to the block is attached a strong staff or handle. To use it, a biscuit-shaped ball of the composition is placed on the rounded surface of the block, which is then in- serted to the flaw and pressed against the bore, using chocks inside the gun as a fulcrum and the handle as a lever. Impressions of the vent may also be taken with lead. The implements required for this are a piece of soft fine wire, about twice the length of the piece ; a stout lever, about the same length, and shod to suit the curve of the bore ; and a small but- ton of soft lead, judged to be of sufficient size to fill the vent at least one inch from the bore. This is pierced lengthwise to re- ceive the wire. To take the impression. Shove the wire through the vent ; let it pass along the bore and out at the muzzle ; put it through the leaden button and tie a knot at the end ; draw the wire back through the vent until the button is introduced firmly into the inner orifice ; apply the lever, making its shoe bear on the button, and force it well in by repeated blows, the muzzle being the fulcrum, or, better, a block of wood placed in the bore as far as the arm will reach. The button is disengaged by pushing in the vent-punch. In taking impressions of the vent and cracks, each button in turn is used as a pattern for moulding its successor. All impressions, however they may be taken, should be most critically examined with a magnifying glass ; otherwise the most important indications will escape observation. Water-proof. Cannon, when inspected upon being received into service, are subjected to an hj'^draulic proof of about 30 pounds to the square inch. This requires a special apparatus 20 306 MODE OF EXAMINING CANNON. not usually found at posts. Nevertheless, useful application of the principle may be made by giving the piece as much elevation as possible, stopping the vent, and tilling it with water. Allow it to stand thus for a few hours, draw off' the water, wipe the bore perfectly dry, and examine with a mirror or lamp. Water seen oozing from any part of the bore indicates a crack or a clus- ter of cavities, a sure sign of serious defects. 563. Mode of examination. The bore should be thoroughly cleaned to detect small defects. If care has previously been taken in keeping a gun tolerably clean, it will probably be suffi- ciently prepared for examination by washing and drying with tow, cotton-waste, or a clean sponge. Should there be hard rust which will not yield, or a thick coating of grease, the bore may be cleaned by tiring (if circumstances permit of it) one or two scaling charges of about one-third the full service charge, with- out projectiles; this will usually loosen the scale. The same may be eff'ected by using hot water and potash, in the following manner : About a gallon of boiling water is poured on one pound of ordinary black potash, and an old sponge, covered with a cloth to make it fit tightly to the bore, is dipped into the solu- tion, and the bore rubbed vk^ith it till the dirt is loosened, when a hard brush will remove it ; it is then wiped dry and slightly oiled. The potash water must be used very hot and the sponge made to fit tightly, or the process is ineffectual. The hard brush is made of wire, and is similar to those used for fowling-pieces. Brushes of bristles — Turk's-heads — are also used. No sharp- edged or pointed scrapers should be emplo3^ed for cleaning the bores of rifled guns, as they would be liable to injure the rifling. The bore, being thus cleaned, should be examined by the aid of a lamp, or if there be bright sunlight, with a mirror. If the bore be slightly wet, the detection of defects is greatly facili- tated. A sharp-pointed pricker is used to ascertain the extent and position of any flaw, the staff" being graduated in inches so that the distance from the muzzle may be readily ascertained. A spring searcher is also used to detect defects, and, with rifles, in such manner that each groove shall be traversed in succession by one of the points. Should a flaw be found, an impression is taken of it. This is done in the manner just described, with gutta-percha, or by using a mixture composed of bees-wax., two parts; treacle., one part; soft soap., one part. The wax should be melted over a slow fire in an iron pot ; the treacle is then added and mixed well by stirring; and lastly the soft soap, a little at a time. The mixture must be kept in motion, and when thoroughly stirred poured out, cooled, and made into balls. This compo- MODE OF EXAMINING CANNON. 307 -sitioii being soft, is always ready for use, but the impression h easily destroyed by handling. The gun should be so placed that the impression will be taken -upwards. In recording the position of any defect, its distance from the muzzle is given in inches, and noted as ""'up," "-right of up," *' right of down," &c., tlie vent always being considered up, and the right or left the sides as they would appear to an observer looking into the muzzle. {Fig. 3, Plate 55.) Impressions of the vent and of the bottom of the bore can be taken properly only by the use of the appropriate instrument; nevertlieless, by the exercise of a little skill and ingenuity, tolerably fair results may be obtained with the improvised instruments just described. Considerable practice is required to get good smooth impressions, and, with the vent, several have sometimes to be taken before one is obtained which can be relied on to show hair- lines. When it is desirable to preserve an impression for future reference or comparison, a label is gnmmed to its back, giving the number of the gun, date of taking it, and the position of the flaw. Should any defects be discovered in the bore (not including the immediate vicinity of the vent) they need not be considered seri- ous, unless, in the case of smooth-bore guns, they are 0.1 incli deep in rear of or 0.2 inch deep in front of the trunnions, or unless they have jagged edges likely to retain pieces of ignited cartridge ; and in the ease of rifled guns, unless, in addition, they are new defects not shown in the memorandum of former inspections, or old ones which have materially increased. Generally speaking, the depth of a defect is of more importance than its extent. With the converted gun, should a defective weld run a consider- able distance around the tube of the bore, it would be liable to part at that point, and the piece should be considered unservice- able. The best method of testing a gun is to take an impression of the defect; then to tire a few rounds witli service charges and take another impression. If, on comparing these impressions, the defect does not appear to have increased, the piece may be considered serviceable. As a precaution against accident, in case -of the splitting of the inner tube of converted rifle guns, sl gas escape or indicator is provided. This is a small hole similar to the vent bored through the cast-iron case on the side opposite the vent, and connecting with a shallow spiral groove cut around the outer tube near the seat of the charge. Should the tube split, smoke will be seen issuing from the hole, and firing should be discontinued. Examination of the vent. Especial care should be given to SOS MODE OF EXAMINING CANNON, this, for the reason that the amount of firing to which a piece- has been subjected is pretty well indicated by the wearing away^ of the vent. The standard gauge (0.2 inch) will be used to ascertain the gen- eral enlargement, and the searcher to detect defects that may have been developed in firing. The vent channel is first thor- onghlj'' cleaned and then tested with a set of cylindrical gauges differing from each other by 0.01 of an inch. The greater the calibre and the heavier the charges, the more rapidly is the wear manifested on the interior and exterior of the vent. The following, however, is the average wearing of the vent for the heavier classes of cast-iron guns. ISTumber of rounds 100 200 300 400 500 Diameter of vent 0.24 0.26 0.30 0.35 0.40 These, combined with examination of the interior orifice, will enable a very correct judgment to be formed of the probable number of fires sustained and the duration of the gun. The enlargement does not extend very far from the lower orifice until the enlargement on the exterior has reached a diam- eter of 0.3 of an inch. So long as the wear is regular and the fissures, although nu- merous, do not exceed 0.5 of an inch, the indications are good. If the cracks are few or diminish in number, running into each other and extending rapidly, it is a very unfavorable sign. Should it be found that the vent has enlarged so as to admit the 0.4-inch gauge, the vent is either bushed or is filled with zinc and a new one bored, as the character of the gun may require. A clean impression should be taken of the bottom of the vent. Unless the proper instrument is provided for doing this, it will be fotuid to be a ditficult operation, and should be repeated several times. If the vent be unbushed, the effect of service is seen by a gradual increase of the channel and by an irregular wearing away of the bottom {Fig. 4, Plate 55) and the formation of fis- sures and hair-lines radiating from tlie edges of the orifice. The extent of these defects is measured on the impression, and if found to be less than half an inch in extent from the original centre, the piece will be reported for bushing or to have a n^w vent bored ; if greater than this, the piece should be reported as unserviceable. The defects usually found around the vents of bushed guns are the giving way of the iron around the bush from the gas getting in between the two metals {Fig. 5), and the fissures or hair-lines which radiate in the iron from the edge of the bush. {Fig. 6.) The metal around the bush gives way almost immedi- ately after a gun is bushed, forming ii hollow ring around it DISABLING CANNON. 309 which gradually increases. So long as this wear is uniform and the edges are not jagged, it. 1.-^ of lirtle importance, and guns need not be rebushed or condemned for this cause until the ring has become 0.1 of an inch deep or 0.1 of an inch wide. If, however, the edges are jagged, or if one side has given way much more than the other, so as to be likely to hold pieces of unconsumed cartridge, tiie examiner must use his discretion as to condemning the gun, it being impossible to lay down fixed i-ules suitable for all cases. Fissures or hair-lines radiating in the iron from the edge of the bush, should be carefully tiaced on the gutta-percha impression, and if they extend more than one-twentieth of the circumference of the bore in any direction, measured from the original centre, the pieces should be condemned. 564. Disabling cannon. 'Vh\f> is either permanent or tem- porary. The first is accomplished by bursting, or \t the piece is rifled, by scoring the siu-face of the bore so as to destroy the efficiencj'' of the rifling. To btu'st a piece, load it with a double charge ; musket or other violent powder is the best; put in a projectile and ram down around it iron wedges, the more tapering thie better; throw sand in to make the wedges take hold, and tiie the piece. If wedges are not at hand, large spikes or similar pieces of iron will answer the purpose ; or load the piece as before, fill it full with its own projectiles, and fire at a high elevation. To fire the piece, when electrical primers are not to be had, prime with fine-grained powder, and place over the vent a p.'ece •of port-fire long enough to permit the man firing it to reach a place of safety before the charge explodes. The port-fire is held in position by being set in clay or putty, or it may be tied to the piece with twine. If port-fire is not at hand, a slow match can, in a few min- utes, be made of any ordinary paper by saturating it with a solution of saltpetre (gunpowder dissolved in water will an- swer); after drying, cut it into strips, and slightly twist them; place one end of a tvvist in contact with the priming of the vent, and apply fire to the other. To disable a piece by scoring the bore, load it with a charge of powder and a shell filled with powder. The shell is without a fuse, and the fuse hole is closed sufficient onlj'^ to keep the powder from spilling out; the shell is inserted with the fuse-end foremost and the piece fired. The bursting of the shell in the bore and the scoring effect of the fragments will moat likely tear 4iway the lands and render the piece unserviceable. Cannon are temporarily disabled to prevent them from being immediately used by the enemy, and also when they are ex- 810 PRESERVATION OF PROJECTILES. pected to be retaken. This operation is accomplished by means of a spike. A spike is made of hardened steel, with a soft point that may be clinched on the inside of the piece. A nail without a head^ or the point of a file, may be used instead of a regular spike. To spike a piece. Drive in tlie spike flush with the outer surface of the vent, and clinch it on the inside with the rammer. To prevent the spike from being blown out, wedge a shot in the bottom of the bore by wrapping it with cloth, or by means of wedges driven in with a bar. To unspike. If the bore is unobstructed and the spike be not screwed or clinched in, put a heavy charge of powder iu the piece and ram jiuik-vvads tightly over it, laying on the bottom of the bore a strip of wood, with a groove on the under side, for a strand of quick match, by which fire is communicated to the charge. Wlien the bore is obstructed, endeavor to drive tlie spike into the bore with a punch. If this succeeds, introduce fine-grain powder into the vent to blow the obstacle out. If, after several trials, neither of these methods succeeds, drill out the spike or drill a new vent. A gun upon an iron carriage is readily dismounted and the carriage disabled by removing the counter-hurters,^ running the piece from battery, throwing the axles in gear, and then tiring it. The recoil will carry the top-carriage oft' the chassis, and the fall will smash it to pieces. If the pintle key be removed, the chassis will also be thrown off and injured. When it is not desirable to fire the piece, the top-carriage may be hauled off by means of a tackle. Preservation of Projectiles. 565. Projectiles for rifle guns should be neither lacquered nor painted, for tlie reason that either of these substances would adhere to and foul the grooves of the piece. When practicable, they should be kept under cover, in a dry place, and if unboxed, should be oiled once a year with sperm oil. They are piled, ac- cording to kind and calibre, on tlieir sides, in tiers of convenient height. The fuse holes should be stopped with tow or cotton- waste. Great care should be taken when handling them to avoid injuring the sabot. No shells of any description should be kept habitually charged. This is done, as occasion requires, when firing. Rifle projectiles for all calibres above 4.5-inch are packed sep- arately in boxes. The boxes have rope handles, and are marked with the kind of projectile. Projectiles thus packed should be- PRESERVATION OF PROJECTILES. 311 stored in a dry place, and not removed from their boxes until required for use. Projectiles for siege guns are packed in boxes, painted differ- ent colors to indicate their contents. Those for solid shot are painted olioe; for shell, black; for case-shot, red; for canister, light drab. The kind of ammunition is furthermore marked, on each end of the box, in Uu"ge white letters, and the place and date of fabrication on the inside of the cover. Each box for siege-gun ammunition contains four projectiles and weighs about 145 pounds. The box is 20 inches long by 11.5 inches wide and 13.5 inches deep, outside measurement; it has two pariitions across it, the space between the partitions holding the car- tridges; the two outside spaces, two projectiles each. The boards of which the partitions are formed are thick enough to allow of a recess being cut in each, in which are carried the req- uisite number of fuses and friction-primers. The boxes have rope beckets on their ends for convenience of handling. Ammunition for the 3.5-inch guns is put up in a similar man- ner, each box containing ten rounds and weighing about 135 pounds. When projectiles of anj^ kind are received at a post, they should be cai-efully examined and gauged, to see that they are of the proper calibre and quality required for the particular piece. Spherical projectiles are lacquered. This is done as soon as possible after they are received. The lacquer used is coal-tar, applied with a brush, as for guns. All rust should be carefully removed, bj^ scraping and wiping, before the lacquer is applied. The projectiles are assorted as to kind and calibre and piled in a dry locality where there is a free circulation of air. The ground is prepared for the base of the pile by raising it above the surrounding level so as to drain oft' the water; it is made level, rammed well, and covered with a layer of sand. The bottom tier of the pile is made of unserviceable balls, buiied about two-thirds of their diameter in the sand ; this base may be made permanent. The pile is then formed, putting the fuse holes of shells downward in the intervals, and not rest- ing on the shells below. The bed may also be made of brick, concrete, or stone pavement, with borders and braces of iron ; or the bed and border may be made of lieavy plank and scant- ling. These, however, in consequence of decay, will require renewing every six or seven years. AVhen for this or any other purpose the pile is taken down, the projectiles should be freshly lacquered. It is generally sufficient that the projectiles be lac- quered, without disturbing the pile, by applying it to those on 312 STORE-HOUSES. the outside. This is done once a year in warm, drj' weather. When the lacquer accumuhites so that the projectiles will not pass through the large gan-ioeo(Mc*-*ioeo T-ic4>a o) o«o«o«o<^>oo«D I •sxi'bS 'no paasuji; 1HO94 o» r^«o«o>oooooo •sqi '■jui'Bd JtoBia I— iiao 00 «o '^ c4 c4 i-H to la la •sqi 'reared aAnO •sqx ':jin'Bd pa^ 'sab 'i[i.op-iCjaxu3 ';«' ';- o fl o oj Qj S ii '-' ^ fee S ?-i TJ -r* -in 0} rt C! H ^ OJ H S "C ,Q S -? 13 P 5 Sjd G AhA^^^^$^. 050S i^ =3 2 bi ^ s o a ^ - 516 PRESERVATION OF POWDER. Armament of Works. d6S. The kind, calibre, and number of cannon constituting the armament of a permanent work, as likewise the emplace- ment of the piece, is determined by the Engineer Bureau. The different parts of a work receive tlieir specific designation from the same source, which likewise numbers, in regular series, the position of the pieces occnpj^ing each part. Tliese numbers, run- ning from right to left as you look outwards, are placed on the parapet opposite the platform. It is the duty of the Engineer Bureau to furnish each work with a chart showing the water channels, with their soundings, and other approaches to the work. From this it is the duty of each artillery officer in charge of pieces to study and familiarize himself with the method of using them so as to make them most effective in carrying out the object for which they were placed in the work. Supply of ammunition. The amount of ammunition which should constitute a supply for artillery in a permanent work, depends so much upon cir- cumstances that no fixed i-ule can be laid down for it. A place li^ible to close siege should be more amply supplied than one Avhich can be replenished, and less would be required to repel attacks from vessels than from a besieging force on land. Two hundred rounds per piece maj^ be taken ordinarily as a good supply for 15-inch guns and the heavier calibres of rifles; greater amounts are required for smaller calibres. For all guns, the projectiles should be about equally divided between shell and solid shot. The amount of ammunition for siege guns, when used in cam- paign as heavy field-pieces, is 200 rounds per piece, together with a small reserve. Preservation of Powder. 569. Powder is kept in magazines constructed with the works. The number of these magazines depends on the number and •calibre of pieces in the work and the probable amount of ammu- nition required for each. Magazines are of two kinds, viz.: storage and service. The former are for the accommodation of powder in bulk ; the latter are smaller than the former, and are placed as convenient as practicable to the pieces to be served, and contain only sufficient powder for immediate use. Adjoining or convenient to each ^service magazine is a filling-room, in which cartridges are made PRESERVATION OF POWDER. 317 up and shells filled. Powder is brought from the magazhie for this purpose, but only in such quantities, at a time, as may bo necessary. In the filling-room are kept the filling implements and such small articles of equipment as are required to be near the pieces. Tlie storage magazines of a post are conspicuously marked A, B, C, &c.; the service magazines are numbered 1, 2, 3, &c., and, in addition, are marked for the particular pieces tliey are to serve. A magazine of sufiicient size, and fitted up with shelves, tables, and racks, is set aside for tlie storage of rockets, port- fires, fuses, primers, slow and quick match, and other similar articles. No such stores will be permitted in a magazine with powder. The keys of the storage magazines are kept by the command- ing officer of the post. Those of the service magazines, unless otherwise ordered, are in possession of the officers having charge of the particular pieces to be served from them, a competent non- commissioned otflcer being assigned to the immediate care of each. The ordnance-sergeant of the post will have charge of the storage magazines and of the one containing fuses, port-fires, &c. Powder is stored in barrels containing 100 pounds each ; the heads of the barrels are painted black, so as to show more plainly the marks, which are stenciled in white. Each barrel is marked on both heads with the number of the barrel, the name of the manufacturer, year of fabrication, and the kind of powder — can- non^ mortar^ musket^ mammoth^ or hexagonal ; the mean initial velocity, and the pressure per square inch on the pressure piston. Each time the powder is proved the initial velocitj^ is marked below the former proof-marks, and the date of trial opposite it. Each manufacturer has, in addition, certain private marks — initial letters — denoting the particular grade to which the powder belongs. A book is kept, by the ordnance-sergeant, which shows, besides all these marks, when the powder was received, where stored, and how much on hand. Barrels of difi^erent kinds of powder are piled separately, and, besides being recorded in the magazine - book, each parcel is marked with a card, showing the kind and the entries and issues. In the magazine, the barrels are placed on their sides, gener- ally three tiers high, or four tiers if absolutel}' necessary. Small skids are placed on the floor and between the several tiers, and the barrels chocked at intervals to prevent rolling. The tiers must be so arranged that the marks can readily be seen and any particular kind reached. There should be an unobstructed space V 318 PRESERVATION OF POWDER. •of several square yards at the door, and this space, as likewise the alleys, should be covered with carpet or matting. The mag- azine is provided with a well near tiie door; into this the sweep- ings are put ; they should never be swept out at the door. For the preservation of tiie magazine, it is of the greatest importaitce to keep unobstructed tlie circulation of air, under as well as above tlie flooring. The magazine should be opened and aired only in clear, dry weather, when the temperature of the air out- side is lower than that inside of the magazine. It should not be ojiened in damp weather if it can be avoided. The ventilators must be kept free and no shrubber}'^ or trees allowed to grow so near as to screen the building from the sun. The magazine yard should be of sand or clay and well drained. The moisture •of a magazine may be absorbed by chloride of lime kept in an open vessel and renewed from time to time. Quick-lime is dan- gerous, and should not be used. Candles, in lanterns, are used for lighting the magazine. ISo one should enter without first removing his shoes or putting India-rubbers over them. No cane, sword, or anything which might occasion sparks, must be carried in. Barrels of powder must not be rolled in transportation; they should be carried in hand-barrows, or in slings made of rope, -canvas, or leather. All implements used in the magazine or on the barrels should be of copper or wood. The barrels must never be repaired in the magazine. When it is necessary to roll them for the better preservation of the powder and to prevent its cak- ing, this is done, with a small number at a time, on boards in the yard. Occasionally, especially in the spring, the barrels should be inspected, and, as far as possible, brushed off, to prevent insects irom destroying the hoops. A light brushing over with carbolic acid will be good for this. When practicable, a sentinel should be posted over the maga- zine, to keep unauthorized persons away and to prevent smoking •or fire within dangerous proximity. The lightning-rods must never be out of repair. Should a fire occur near the magazine, the ventilators and windows must be immediately closed, and the building covered, if possible, with paiilins, blankets, or carpets saturated with water. It is extremel}'^ hazardous to attempt to remove the con- tents at such a time. Neither loaded shells, fire-works, nor composition for fire- works will be stored in a magazine with powder. Shells should be filled in the filling-room of the service magazine. Transportation. In v^^agons, the barrels of powder must be FILLING CARTRIDGE-BAGS. 319 packed in straw, secured in such a manner as not to rub against each other, and the load closelj'- covered with canvas. Sufficient guard should accompany the ti-ain to prevent all smokino; or lire near the wagons. I^o camp-fires should be allowed near the park. On railroads, each barrel should be tightly boxed and packed so as to avoid friction ; the cars, if practicable, sliould have springs similar to those for passenger cars. 570. Filling cartridge-hags. Cartridges for all pieces larger than the siego gun should be made up only as required for use, and when any are left over after firing, they are stored away in the service magazine on shelves. The cartridges are filled in the Jilling-room of the service magazine. Under no circumstances will filling be done in a powder magazine. The powder, in bar- rels, is carried from the storage magazine to the service maga- zine in powder-carts or hand-barrows. To fill the cartridges, the implements required are : One cop- per liammer^ one wooden drifts one counter hrusJi^ one scoop., one counter scales and weights (brass or copper), one filling funnel., one set powder measures., cartridge-hags, and twine. The barrels are opened by first loosening the upper hoops, when the heads can be taken out easily. Care should be taken not to handle the barrels or powder roughly. Should the powder be caked or lumpy, caution should be ex- ercised in breaking the lumps. When the lumps are small and not very hard, they may be broken by pressing them with the hands ; but when large and hard, requiring more force to break, the powder is taken to some safe place away from the magazine, spread upon a paulin, and broken with a mallet. The grains must be separated, but not crushed. When cartridges are to be used with projectiles, the powder is carefully weighed ; for blank cartridges, it is measured. When the piece for which the cartridges are to be prepared has a cali- bre of less than 7 inches, the filling funnel is used, one man hold- ing open the mouth of the bag while another pours the powder into it through the funnel. The bag is then tied with twine close to the powder. For cartridges of more than 7 inches diam- eter, the powder is poured into the bag by means of the scoop ; the bag is tied as before. When cartridges are filled, each one should be marked with a pencil or by stenciling, showing the kind and weight of powder and for what kind of piece it is to be used. TRANSPORTATION OF ARTILLERY. To Embark and Disembark Artillery and Artillery Stores, General Rules. 571. When artillery and its stores are to be shipped for an expedition, prepare first a list of all the articles, stating their number, individual weight, and the total weight of each kind. In estimating the weights, allow double for that of bulky articlf^s which occupy ranch space without weighing much. Divide the total quantity to be transported among the vessels, and make statements in duplicate of the articles on board each vessel, one of which lists should go with the vessel and the other remain with the officer shipping the stores. The articles must be divided among the vessels according to the circumstances of the case ; but, as a general rule, place in each vessel everything necessary for the service required at the moment of disembarkation, so that there will be no inconven- ience should other vessels be delayed. If a siege is to be undertaken, place in each vessel with each piece of artillery its implements, ammunition, and the carriages necessary to transport the whole or a part; the platforms, tools, instruments, and materials for constructing batteries; skids, rollers, scantling, and plank. If a particular calibre of gun is necessary for any operation, do not place all of one kind in one vessel, to avoid being entirely deprived of them by an accident to it. Dismount the carriages, wagons, and limbers by taking off the wheels and boxes and, if absolutely necessary, the axle- trees. Place in the boxes the linch-pins, washers, &c., with the tools required for putting the carriage together again. Number each cai'riage, and mark each detached article with the number of the carriage to which it belongs. The fixed ammunition must be carefully packed in its pre- scribed boxes ; the cartridge-bags, fuses for shells, and their ammunition, either in substantial boxes with rope handles or in 21 ( 321 ) 322 TRANSPORTATION OF ARTILLERY. barrels ; powder in barrels, in a magazine constructed in a vessel to hold it. Sponges, rammers, worms, and ladles should be united in bundles ; other implements, intrenching tools, levels, rules, &c., in bundles or boxes; implements, in bundles and boxes of com- plete sets, as far as practicable. Small-arms should be in their prescribed boxes. The contents of each box, barrel, or bundle should be marked distinctly upon it. The boxes should be made small for the convenience of handling, and have rope handles to lift them by. The position of the different articles in each vessel should be noted in a column in the list on board. Place the heaviest articles below, beginning with the shot and shells, (empty,) then the guns, platforms, carriages, wagons, limbers, ammunition-boxes, &c. Boxes of small-arms and am- munition in the driest and least exposed part of the vessel. The skids, scantling, and boards may be in the more exposed parts, or in the run. Articles required to be disembarked first should be put in last, or so placed that they can be readily got at. If the disembarkation is to be performed in front of the enemy, some of the field-pieces should be so placed that they can be dis- embarked immediately with their carriages, implements, and ammunition ; also the tools and materials for throwing up tem- porary intrenchments on landing. When there are several vessels laden with artillery and stores for the expedition, each vessel should have on each quarter and on a signal at mast-head a number that can be easily distin- guished at a distance. The same number should be entered on a list of supplies shipped in each vessel. The commander can then know exactly what resources he has with him. Some vessels, distinguished by particular signal, should be laden solely with such powder and ammunition as may not be required for the immediate service of the pieces. If it is necessary to reship or leave any articles on board the vessels, care should be taken to note them on the list. Boats of proper capacitj'^ must be provided for the disembarka- tion, according to the circumstances in each case. It may be necessary to establish temporary wharves on tres- tles, and to erect shears, cranes, or derric]«. .On a smooth sandy beach, heavy pieces, &c., may be landed by rolling them overboard as soon as the boats ground, and hauling them up with sling-carts. 572. Railroad transportation. The most suitable car for carrying horses, especially in warm weather, is the ^*sla^ stock- TRANSPORTATION OF ARTILLERY. 323 «car," built of slats and open all around, but tight in roof. Another kind, known as the "combination car," is made with live doors on each side and one at each end, which may be closed tight for stores, or with iron grates when carrying horses. These are suitable for either warm or cold weather. Both kinds are usually 27 feet 4 inches long, 7 feet 9 inches wide, and 6 feet 8 inches high, inside measurement. Each car will carry fourteen artillery or sixteen common horses or mules. The horses all face towards the same side of the car, and are hitched by their halters to the frame-work. If the journey is to be continued beyond eighteen or twenty hours, the horses will require to be watered and fed. ^N'ose-bags are generally used for the grain. If the drivers are attentive, they, by taking advantage of the short halts made by the train, can feed grain and hay quite easily by hand. Half rations will be sufficient under an}' circumstances. Before placing the horses on the cars, they should be thoroughly groomed and cooled; they should iiave nothing more on them than their halters. If the Journey is to continue for several days, (but never be- yond four without unloading,) the horses should stand length- wise of the car, facing each other, and hitched to two bars placed for the purpose across the car. The bars have space between them sufficient for feeding purposes and for a man to remain in charge. When thus arranged only about one-half as many can be carried in each car as in the other case. By load- ing in this way, close "box "-cars may, even in hot weather, be used, the doors being left open for ventilation. Horses are best loaded and unloaded from a "stock shute," but where this convenience is not available, and there is no plat- form, a ramp or shute may be improvised, using for it planks about 12 feet long and from 2 to 3 inches thick, depending on the strength of the wood. The ramp should be about four feet wide, with the planks firmly fastened together with transverse battens. These battens, furthermore, prevent the horses from slipping. A strong trestle or crib of logs supports the end of the ramp next the car, while the other rests on the ground and is secured from slipping by strong stakes. An intermediate trestle or a support of logs should be placed to prevent the planks from springing with the weigiit of the horses. Three or four posts of suitable height are set in the ground on each side, to which side rails are lashed or spiked for the purpose of keeping the horses from stepping off. A board' should be placed on each side to prevent the horses' feet from slipping over the edges of the planks. When planks 324 TRANSPORTATION OF ARTILLERY. are not procurable, a ramp of earth, supported bj^ means of logs^ or stone on the end next the track, may be constructed. The cars are brought up in succession to the ramp to be loaded or unloaded. Mules and ordinary horses are usually driven in loose and stand unhitched. In the field, where no shute or ramp is to be found at the place of unloading, material ready prepared for constructing one should be carried with the train. Artillery carriages and transportation-wagons are carried on platform or '•'flat " cars. Tiiese cars are generally 28 feet long by 8 feet wide. When properly loaded each will carry two field guns and two caissons complete. To load them the carriages are unlimbered and the spare wheels removed from the caissons; the rear train of a caisson, its stock to tlie rear, is run to the front end of the car and its stock rested on the floor; anothei* rear train is run forward in like manner until its wiieels strike or overlap those of tlie first, when its stock is rested on the floor. A limber is then placed on the car with its pole to the front, resting on the rear train ; the second limber is backed on and its pole held up until a gun, trail foremost, is run under it; the trail of the gun is rested on the floor and the pole of the limbei- on the gun carriage. The other gun is run on in the same manner, and its trail rested on the floor under the first gun ; a limber is next run on and its pole rested on the last gun ; the remaining limber is run on with its pole under the preceding limber. All of the carriages are pushed together as closely as possible and firmly lashed. Where the carriages are liable to chafe each other, they are bound with gunny-sacking or other stufT. A side platform, such as are fou!id in depots, is the best for loading. The carriages are first run onto a spare car; from this they are crossed over on planks to the one upon which they are to be carried, and arranged on it as already described. When there is no side platform, the carriages are run up at the end of the car b}' means of way-planks. Siege guns can be loaded and carried in a similar manner, but when there is no side platform, blocks and tackle will be required for hauling them up the way-planks. Two siege guns with their carriages and limbers complete can be carried on one car, and, in addition, boxes of ammunition or stores may be piled between and underneath the carriages. One '"flat" car will carry two army transportation-wagons standing, besides a large quantity of other material. If the wagons are '•'"knocked down^'''' the same car will carry four. Twenty-four tliousand pounds is considered a safe load for one TRANSPORTATION OF ARTILLERY BY SEA. 325 car on a good track. Baggage, harness, forage, &c., are usually carried in box-cars. These cars have the same dimensions as heretofore given for those carrying horses. The average size passenger car will seat sixty men, but a small car will seat only fifty. The men must be provided with cooked rations for the whole trip. Each car must be liberally supplied with drinking water, lights at night, and all other conveniences, to make it unnecessary for the men to leave them during stop- pages of the train. The officer in command of troops on a train will act in har- mony with the railroad officials, and must not interfere in any manner whatever with the running of the train. Ten to fifteen passenger or sixteen to twenty-two freight cars go to make up a train drawn by one locomotive ; but when the grades are light and but little curvature in the road, the maximum weight of trains may reach double these figures. Passenger trains generally travel at the rate of about tw^enty- two miles per hour, and freight trains about fifteen, including customary stoppages. Troop trains should not be dispatched from a station with less intervals than ten minutes between them. The experience gained during the war of the rebellion shows that to supply an army of 100,000 men in the field by means of a single line of rails, the proportion of rolling stock should be — engines 0.25 and freight cars 6.0 to every mile of road. This does not provide for the conveyance of troops. In calculating the amount of rolling stock available for use, a deduction of 50 per cent, for locomotives and 30 per cent, for all other carriages must be made for those usually undergoing repairs. From the foregoing data, a small calculation will give the amount of railroad transportation required for any given num- ber of troops, artillery, or material, and the capacity of a road for performing the work. 573. Transportation of artillerij hy sea. In the United States service there are no vessels fitted up especially for transportation of troops, horses, or artillery material. Even during the four years of the war of the rebellion no attempt was made towards it further than temporary arrangements for some particular voy- age. The voyages were short, lasting generally only two or three days, never exceeding eight. Embarking and disembark- ing were usually accomplished with wharf facilities. In only three or four instances were the movements of an expeditionary character, requiring these operations to be performed on an open beach or in front of the enemy. As desirable and advantageous ::as it would have been to have had suitable transports properly 826 TRANSPORTATION OF ARTILLERY BY SEA. fitted up, the absolute necessity for it was never felt, and conse— quentl.y they were never adopted. It maj^ not always occur that the same conditions will exist, and it is therefore well to collect such information on the subject as may be needed. Tlie horses and material belonging- to artillerj'^ require so great an amount of space in proportion to that required for the men, the latter need scarcely be taken into account when esti- mating for ship room. Any vessel capable of carrying' horses and guns will accommodate the men belonging to them in those parts where neither horses nor guns can be stowed. Guns, caissons, ammunition, and other material of this char- acter are cai'ried in the same manner as ordinary merchandise. When once within reach of the ship's tackle, the officers and crew of the vessel will know how to stow and take care of them to the best advantage. When practicable, it is not only the most expedi- tious, but altogether the best way to leave the carnages mounted. The length of the voyage and the character and capacity of the vessel will determine whether or not this should be done, and in what part of the ship stored. Other considerations, such as facilities for embarking and disembarking, will likewise go to determine these questions. The horses are more difficult to provide for, and it is with ref- erence to their accommodation and safety that vessels for the transportation of artillery sliould be selected. During tlie rebellion a species of transportation was employed upon the Chesapeake Bay, and even for short voyages at sea, which proved ver}'- successful, and which might again find useful application. Tliis consisted in embarking the horses on large schooners and the batteries on steamers, (frequentlj^ ferry-boats,) which, tak- ing the scliooners in tow, conducted them to their destination. Eacli schooner carried upon an average fifty horses; three were therefore required for one battery. The ferry-boat carried easily the material of two batteries. The advantage of this kind of transportation consisted chiefly in the ease of loading and un- loading tile vessels. Their light (h-aught enabled them to lie up to almost any kind of wharf. Strong gang-planks were pro- vided, over which the horses were led to the decks of tlie schooners, upon which they stood, facing outwards. To prevent them from gnawing and injuring the gunwales, stout boards were temporarily nailed thereon. The batteries were run by hand onto the feny-boats, the carriages unlimbered and stowed, the whole occupying but a few minutes of time. Disembarking- was accomplished with equal facility. TRANSPORTATION OF ARTILLERY BY SEA. 827 Each schooner carried its due proportion of the men of the batter}'-, who looked after the hoi-ses. When the voyage is to extend beyond six or seven days at sea, the vessel should have room between decks where stalls can be fitted up in the manner hereinafter described. But if the voyage is of shorter duration, stalls are not absolutely necessary. In this case the vessel best adapted is a long low steamer, with a clear upper deck for the accommodation of the horses. The guns, carriages, harness, and baggage are stowed between decks, where likewise the men find ample room. In many steamers a large gangway on each side leads to the main deck, through which the carriages can be run by hand. In vessels not so provided they have to be lowered by means of tackle down the main hatch, — a slow and laborious process. Horses, in all cases, should stand ath wart-ship; in this posi- tion they better accommodate themselves to the rolling motion of the vessel. When on the upper deck they should face in- wards ; this, for the reason that the spray will not then strike them in their faces, and, besides, when facing each other in this manner they will suffer less from fright and nervous excitement. A vessel of not less than 25 feet beam will accommodate two rows of horses, leaving a space between the rows, and between the croups of the animals and the sides of the ship, ample for the proper care of the horses. These spaces are, furthermore, necessary as gangways for working the vessel. The average artillery horse occupies a deck space of 8 feet b}^ 2 feet 4 inches. It results, therefore, that the whole lengtii of the deck in feet divided by the last dimension will give the number that maj'' be accommodated in each row. As they stand better when close together, side by side, no allowance need be made for vacant space between them. The horses are secured by their halters to hitching-bars (B B, Fig. 1, Plate 56), of strong scantling, running longitudinally in two lines along the deck. A space of about five feet is left between the lines for the gangwa}^ before mentioned. These bars should be about four feet from the deck, and supported by stanchions (A A) secured to the deck by strong angle-irons fast- ened with screws. The bars are braced from the sides of tlie vessel with stout scantling (C C). These braces are arranged so that the spaces between them will include rive horses, (more or less, depending upon the strength required to give entire secu- rity to the structure,) and are fastened with bolts and nuts, so that in loading they ma}' be removed and replaced successively as the horses are put in their places. The}'- must be smoothed oft", or wrapped with gunny or other material, to i^revent tlieir 328 TRANSPORTATION OF ARTILLERY BY SEA. chafing the horses. Holes are bored or i-iiigs attached to the h itching-bars for the halter-straps The horses should be hitched short, and when putting them on board care should be observed to have those accustomed to each other placed togetiier. Kick- ing and vicious animals are placed, as far as practicable, where they can do least mischief. AH stalls, hitching-bars, or whatever other arrangement for eecuring horses, must be strong beyond any possibilit^'^ of giving way. The living force exerted by a row of horses as they swing with the motion of a ship in a heavy sea-way, is very great, and it is better to have no securing arrangements whatever than to have those that, by giving way, will wound and injure the ani- mals in the wreck. If the transport is to be used in very inclement weather, the spar deck, over the liorses, should be covered. Canvas stretched over a secure frame is better than boards, as the latter, in a severe storm, might be carried away, and its wreck would cause disaster among tiie liorses. During heavy weatlier, horses sometimes become exhausted and fall. The best thing that can be done in such cases is to back out the horse on each side, so as to give the fallen horse plenty of room. The next horses adjoining are prevented from trampling him by having placed against them braces such as heretofore described. There should be several of these braces spare foi- this special purpose. The fallen horse should be pro- tected from rain and spraj' by a paulin, and great care and ten- derness exercised towards him ; otherwise he is very liable to perish. The horses may be fed from nose-bags, but it is better to have for each one a small trough, suspended to the hitching- bar by means of two iron hooks passing over the bar. The troughs are moved out of the way when not in use. Haj'' can be fed to them by tying it up tightly in bundles with rope-yarn and fastening the bundles to the hitching-b;i.r. It may also be fed in small quantities by hand, and the more attention the horses receive in this way from the men, the less fretful and uneasy they become. When the embarkation takes place from a wharf, and the ves- sel is not too high, it is best to use gang-planks and lead the horses on board. The gang-plank leading up from the wharf to the gunwale should be about 20 feet long by 10 wide, aiul be made vei-y strong. This width admits of its being used for gun carriages. It should be provided with ropes at the corners, rollers, side rails, and boards upon the sides to prevent the horses from getting their feet over the edges. Another similar gang-plank, but not so long, leads from the gunwale to the SLING. 329 deck, the two being securely fastened together by their ropes. These gang-phini<8 should be carried^ by the vessel, ready for |it'lls, the epaiilment must be made consid- erably thicker than thVactual peneti-ation of the projectiles used against it. Formerly tA.i'^ additional thickness was put down at one-half, but this is man'^estly greater than is necessary for the artillery now in use. An addition of one-third dlthe maximum- penetration is ample. Assuming this as the rule, parapets constructed of ordinary earth — i. e., clay and sand mix^'d and well rammed — should liave the following thicknesses : i^aw^e 150Q yards — To resist 12-inch rifle, 45 feet; 10-inch rifle, 35 !eet; 8-inch rifle, 25 feet; 6.4- inch rifle, 22 feet ; 15-inch smoo'Ji-bore, 3Q feet. Range 1000- yards — To resist 4.5-inch rifle, 16 feet; 3.67-inch rifle, 15 feet; 3-inch rifle, 14 feet. For parapets constructed of sandv Range 1500 yards — To- resist 12-inch rifle, 30 feet; 10-inch jifle, 25 feet; 8-inch rifle^ 20 feet; 6.4-inch rifle, 18 feet; 15-lnch smooth-bore, 25 feet. Common earth, (mixture of clay and Si»d,) loosel}^ thrown np^ offers much less resistance to penetratDi^ than when settled ; with sand the diff'erence is not so great. Interior revetments of ordinary thickness, whether of ma- sonry, sods, or gabions, give but little addiuonal resisting power to a parapet, and should not therefore be taken into accoiuit when estimating its thickness. From experiments made for the purpose ^f determining the best form and dimensions for masonry breast-height walls, it was found that 15-inch smooth-bore projectiles filed at a butt 200^ yards distant, after passing through 20 feet of \\ell-rammed sand» overturned a wall of best-laid granite masonry \ feet thick and 5 feet high. The penetration was but little inferOi'to that of sim- ilar shot fired into unsupported sand. The projectiles, although not coming in actual contact with the wall, (in most instaiices lodging several feet from it,) transmitted the fo'ce of their im- pact through the intervening sand, eacii one fd'cing the wall more and more from the perpendicular, until at ^»e sixth it fell bodily. With a parapet of 12 feet of well-rammed sand against a breast- height wall of concrete 6.5 feet high, 5 feet thick at ipp and 7 feet 2 inches at bottom, pi-ojectiles from the same gun, V'th a range of 430 yards, demolished the wall; not, however, a^i" the pre- ceding ease, by overturning it, but b}^ cracking and crumbling^ it. In this case the shot penetrated to the concrete anci destroyed it by direct impact. ^ With a parapet of 9 feet of sand against a concrete breast- height wall 8 feet thick at top and 10 feet 2 inches ii bottom. PENETRATION OF RIFLE-MUSK^T. 363^ projectiles from a 12-inch rifle, at a range of 430 yards, demol- ished the wall in a manner j»imilar to the foregoing case. With a parapet of 7 feet of sand against a concrete breast- height wall 10 feet tliick at top and 12 feet 2 inches at bottom, projectiles from a lo-incli smooth-bore gun (the range being as above) cracked the wall, but did little or no other damage to it. In these experiments it was denvonstrated that when the wall is stont enough to resist the projectiles, the latter invariably glance upwards and, passing out through the interior crest, fail within the parapet at distances varying from a few yards up to- a thousand or more. After thus glancing they are still capable of doing considerable damage to the interior of a work. These facts go to prove that however massive a sustaining wall may be, there should be sufficient earth in front of it to arrest the projectiles the same as though there v/ere no wall at all. Hence it will be economy of labor, material, and space to have revetments as slight as is consistent with the object of holding up the earth of the parapet. 597. Penetration of shells from mortars. In sand and in compact clayey earths, such as would generally be employed for the coverings of magazines and bomb-proofs, the penetration of mortar shells falling with maximum velocities is about three times their diameters; but in order that the lining of the maga- zine or bomb-proof may not be injured by their impact, double this thickness should be given. Shells fired from guns at high elevation possess many of the properties of mortar shells; but as the velocity is much greater, the penetration also is greater, and their effect upon striking is more destructive; consequently, additional thickness of earth is required for magazines and bomb-proofs exposed to this kind of fire. In clayey earth the mouth of the crater formed by the explo- sion of a raoi-tar shell is about four times the diameter of the shell ; in snnd it is considerably less. The maximum velocity of a descending mortar shell is 419 feet per second, or about one-third that of the striking velocity of projectiles fired from guns at ordinary distances. This accounts for the comparatively small penetration of the former. Shells of any kind striking on marshy ground hnvj themselves so deeply as to produce but little effect by explosion. 598. Penetration of rifle-musket. Kecorded experiments give somewhat conflicting results on this head, but, to be on the safe side, the following thicknesses appear to be needful to give security against infantrj^ fire : Clay, loosely thrown up, 4 feet; sandy or gravelly earth, loosely thrown up, 3 feet; sand-baga. :864 \ INTBEI^OHED CAMPS. \ "^ iilled, 1.25 feet; gafeions (wicker), filled with earth, 1.75 to 2 feet; phie (soft), 16 toNiS inches; oak and elm (green), 6 inches; ?ish (green), 4.5 inches ^^ap-roller and fascines (green), 12 to 15 nches; brick-work, 4.5 ihfihes; boiler-plate, ^^ inch, nie above are for distairces not exceeding 100 yards; beyond that, penetration diminished rapidly with the range. At a dis- tance of twenty yards a rope mantlet 4 inches tliick is proof •against a rifle-musket shot. As weight is a consideration in mantlets, they need not be giv(3n a gieater thickness than this to insure all necessary security from such fire. 599. Field intrenchments may be classified as follows : 1. Intrenched camps; 2. Intrenched lines of battle; 3. Detached nvorks; 4. Lines of works; 5. Works auxiliary to permanent fortifications ; 6. Works for sieing forces remain, usually expend- ing, without much effect, a large amount of ammunition, until one or the other withdraws for the purpose of making a new move. The operation of withdrawing is one of great delicac3V -866 DETACHED WORKS. •and is generally performed at night with all possible secrecy. The artillery commanders at such times have to exercise great care and foresight, that their batteries may take the proper routes and not obstruct their own movements oi- those of otlier troops. An officer from each battery should make himself familiar with the road to be taken by it, and act as its guide. 603. Detached works are those that are situated beyond the range of fire of any other works, and which, for their security, have to rely upon their own strength and resources. The object of such works is to defend and hold isolated points that are of importance; such as railroad or other bridges, mountain passes, narrow defiles, fords, points upon rivers to -close them against the passage of hostile vessels, &c. The char- acter and extent of a work of this class will depend upon the degree of importance attached to the object for which it is con- structed, the amount of force available . for its occupancy, and the nature of the locality. In every instance, artillery would form an important element in its means of defense, and the posi- tion of the work should be selected so as to allow free use of it. Works of this kind may be classified under three heads : 1st. Those which, being secure on the flanks and in the rear, are assailable only in front. Under this class may be placed open batteries located on the banks of rivers, or at the entrance of harbors, to prevent the passage of an enemj'^'s vessels. 2d. Those which are assailable in front and on the flanks, but not in rear. 3d. Those which are assailable on all sides. 604. First class. This is applicable to narrow defiles where the flanks are secure against being turned. {Fig. 1, Plate 57.) When the width of the defile is not greater than 1800 yards, the line may be a straight one (AB) for infantry, with short ad- vanced lines on the flanks, as represented in the figure, for artil- ler3^ Should the conformation of the ground be not suitable for placing artillery precisely as represented in the figure, then the most commanding position on some other part of the line will be selected for it, bearing in mind always to secure as far as possi- ble cross-fire over the ground in front. When the defile exceeds 1800 yards in width, a cremaiUere or serrated line is adopted, and •on it the artillery is disposed as represented in Fig. 2, Plate 57. 605. Second class. The plan of works of the second class admits of great varietj', depending on the extent of the position. The most simple is that of a work of only two faces, the salient being towards the assailant's line of approach. This work is termed a redan. {Fig. 3, Plate 57.) AB, gorge; AC and BD, faces; CD, pan-couple; BE, a small fiank sometimes used. STRENGTH OF GARRISON. 367 The faces should receive such direction as to sweep the ap- proaches to the flanks of the position. As many pieces as possi- ble are placed in the salient, and others disposed alon^ the faces in the most coramandin^^ positions for sweeping the ground in their front. The angle formed at the salient by the faces should never be less than 60°. This rule is general for all salients. 606. When the flank approaciies extend somewliat to the rear, (as in Fig. 4, Plate 57,) a flank is added to each face of the redan ; it then becomes a lunette. The flanks receive such direc- tions as will sweep by their fire that portion of the flank ap- proaciies whicli cannot be reached from the faces except by a very oblique fire. BC and CD are the faces; AB and DE, the flanks. The artillery is placed in position at the salients, in each of which is a pan-couple. GOT*. Third class. The works comprised in this class are termed inclosed works; as, beina^ assailable on all sides, they must, for security, present a complete line throughout to any assault. These works may be divided into three orders: 1st. Polygonal works., or redoubts ; 2d. Tenailled works., or star forts ; 3d. Bas- tioned works. 608. Redoubts. These are polygonal figures having anj^ number of sides; and when the site is horizontal, or sensibly so within cannon range, there is no reason for adopting anj^ other than a regular polygon for a plan. The most simple, and the one usually taken, is the square, {Fig. 5, Plate 57,) the angles of whicli are formed into pan -couples for the reception of artillerj''. The size to be given to a redoubt, or generally to any inclosed work, will depend upon the number of men available for its defense, taking it as an established rule that it is better to have a force concentrated than too much distributed, and therefore injudicious to make works of a greater extent than can be well manned and vigorously defended. The number of men will depend upon the particular circumstances of the case; as, for instance, its situation with regard to distance from the enemy ; whether it is liltely to be attacked by a powerful force or only by raiding parties ; whether it is of such vital importance as to require it to be heM at all hazards, and its distance from sup- porting force. 609. Strength of garrison. One double-rank file — that is, two men — is required for the defense of every lineal yard of parapet; the number of yards in the crest-line of any redoubt •should not, therefore, exceed half the number of men to be con- 368 STAR FORTS. tainecl in it. This number makes allowance for the sick and the various details and duties which deplete the effective strength of garrisons. For the actual defense of lines, with modern arms, one man per lineal j'^ard is ample. Every man in an inclosed work requires for lodojing-room 3 square yards of the interior space ; that space, clear of the ban- quette, magazines, gun spaces, and traverses, must not therefore contain less than three times as many square yarth of side for a square redoubt capable of holding artillery is 40 j^^ards ; this gives a work capable of con- taining one field-piece at eacii angle and about 250 men. The redoubt has sectors without fire, except that delivered from the pan-couples, and is without flanking arrangements. 610. Star forts. A star fort in plan consists of a polygon having alternately salient and reentering angles. The object of this disposition is to obtain cross-fires on the; approaches to the salients. The simplest form of the star fort is planned by ])lac- ing redans on the middle of the faces of a square redoubt, {Ficf^ 6, Plate 57,) thus giving alternate salients of 90 degrees and 60^ degrees. A B C D, square redoubt ; ahcd^ redans. The guns would naturally occupy the pan-couples of the at- tached redans, and likewise those of the square. The star fort, from its imperfect flanking dispositions, is but little, if at all, superior in strength to tlie redoubt. For the same interior space for the uses of the garrison, the star fort presents a much longer line of parapet to be defended than the redoubt. It is therefore only on iuregular sites or broken ground that application of it will be found advantageous. Remarks, — Since the introduction of modern improved arms. BASTIONED FORTS. 369 but little reo^arcl has been given to flanking arrangements in field- works, experience liaving developed the fact that they are of very little practical advantage. Lines and groups of works are now laid out so as to cover each other by flank and cross-fire. A work entirely detached should, however, have within itself flanking arrangements. 611. Bastioned forts. The bastioned fort has been devised to remedy the defective flanking dispositions of the preceding classes of works. This fort may consist of a polygon of any number of sides, but for field forts the square and pentagon are generally preferred, on account of economy of labor in construction. To plan a work of this kind, a square (A B K, &c.. Fig, 1, Plate 58) or a pentagon is laid out, and the sides bisected by perpendiculars; a distance (C D) equal to one-eighth of tlie side is set off on tlie perpendic- ular in the square, or one-seventh in the pentagon; from the angular points of the polygon, lines (AU and HB) are drawn through the points thus set off"; these lines give tlie direction of the lines of defense; from the salients of the polygon distances (AE and FB) equal to two-sevenths of the side are set ofi'on the directions of the lines of defense, giving the faces; from the extremity of the faces the flanks (E H and F G) are drawn per- pendicular to the line of defense of the other face of the same front; the extremities of the flanks are connected by a straight line termed the curtain. A B is the exterior side ; H, the angle of the curtain ; C D, the perpendicular; H B, the line of defense; A, the salient angle; A E, the face ; F, the shouldcn- angle ; E H, the flank ; B P, the capital; HG, the curtains; GO, the gorge of bastion; CAE, the diminished angle. The side of the polygon is termed the exterior side; the line bisecting it, the perpendicular ; the angle at the salient is the flanked angle; the one formed by a face and flank, the sJiouldcr angle; the one between the flank and cnrtain, the angle of the curtain; tlie line bisecting a bastion, the capital; the portion of the work inclnded between the capitals of two adjacent bastions is denominated a bastioned fronts or simply 2i front; the interior space of tlie work not included in the bastions is called the parade. Eemark.— The foregoing nomenclature applies also to perma- nent works. In the latter class the parapet is generally much above the parade. The space behind the parapet for the accom- modation of the guns is termed the terre-plein, which is united witli the parade by earthen slopes or vertical walls. Communi- cation with the parade and terre-plein is generally provided for 24 370 BASTIONED FORTS. by means of roadways termed ramps. The whole mass of struct- ure thus raised above the parade is called the rampart. An examination of the arrangement of a bastioned front shows that there are neither dead angles nor sectors without fire ; that the salients, and all the ground within range of fire, are pro- tected by columns of direct, flanlv, and cross fire. Permanent fortifications are, when the site admits of it, con- structed on the bastioned-front principle, and generally have auxiliarj'' outworlvs, which are usually omitted in field-worlvs. The object for which permanent worlds arc erected is to afford a powerful artillery fire, and the entire interior crest may, there- fore, be occupied by cannon. In field-works tlie proportion of artillery is less, and is usually disposed of b}^ placing a piece in each pan-coiip^e, two or more on each face and one on each flank, leaving the curtains entirely free for infantr3% Siege howitzers, when used, are placed on the flanks, where their capacity for tiring canister is most serviceable in sweeping the ditch in front of the opposite face. Machine guns occupy a like position. The sides of the pol3'^gon upon which a bastioned fort is laid oflf should not exceed 600 yards, nor be less than 125 yards. If greater than the former, the range from the flanks will be too great to cover properly the salients of the bastions ; if less than 125 yards, the flanks will be too short for efficiency, and the bastions too restricted in space for artillery. Calling the exterior side X, the parts of the front will be as follows : Diminished angle =14° 2^ 10^ Salient angle . =61° 55^ 40^ Shoulder angle . =118° 4^ 20^ Curtain angle . =1040 2^0^ Line of defense=0.71804 X Face . . . =0.2857 X Flank . . . =0.10808 X Curtain . . =0.39320 X Gorge . . . =0.18279 X The entire front is equal to X multiplied by 1.1824. With a pentagon the above numbers are slightly changed, but so slightly as to make no appreciable difference when estimating the dimensions of the sides of a polj''gon for a bastioned work to accommodate a specified number of men. In making an esti- mate for the number of men required to man the parapet of a work, no allowance is made for the space occupied by guns ; this, for the reason that the number of men so required is about equal to that of infantry for tiie same space ; that is, two men for each lineal yard of interior crest. AT F The foregoing is expressed by ■2L= g x N X 1.1824 In which F = the number of men: S = the number of sides BASTIONED FORTS. 871 of the polygon ; and N = the nnmber of men per yard of interior •crest; X beinj^, as before, the exterior side. In actnal field service, it seldom happens that the ground will admit of a bastioned work constructed on a regular polygon ; but whatever it may be, the foregoing principles will apply and give a close approximation to the size of the required work. To ascertain the number of men required to man a given work, measure the interior crest (in yards) and multiply by 2. Allowing two men for each yard of parapet, the exterior sides of a square bastioned fort to accommodate 4000 men would be 422.8 yards. A fair proportion of artillerj'^ for a work requiring 4000 men would be 36 guns, disposed of as represented in the figure — i. c, one in the salient of each bastion; one on each flank ; one in the shoulder angle, and two on each face. A bastioned work constructed on a square of 125 yards will accommodate about 1180 men and an armament of 8 pieces. 612. For ordinary field-works the pieces would generally be those on traveling carriages, and consequentl}'' readily moved from one part of the work to another, as required by the nature of the attack. As a general rule, the heaviest pieces would be placed in the salients, and howitzers, if used, in the flanks to sweep the ditch with canister. Machine guns are especially adapted to the defense of field- works, and should never be omitted as part of the armament. Being breech-loading and easily handled, they require but little exposure either for themselves or the cannoneers. The oscillat- ing apparatus with which they are provided allows the fire to be delivered in a horizontal line, which is superior to the cone of dispersion of canister from howitzers or guns. When practica- ble, the machine gun should be fired from a platform ; but as the piece is light and the recoil small, the platform may be slight and laid without counter-slope. As a general rule, all platforms for pieces on traveling carriages should be laid horizontally, as this enables them to be fired in any direction with equal facility. A bag of earth placed at a proper distance behind each wheel will check recoil. Since the fire of the Gatling gun is that of infantry alone, its introduction should not diminish the amount of artillery prop- erl)'- requisite for a work. Machine gnns may partly replace infantry, but not artillery. Whenever practicable, mortars should constitute a part of the armament of field-works. These should be placed in such posi- tions, usually behind traverses, as not to prevent, bj'' their blast. 872 LINES OF WORKS, any portion of the parapet from being occupied by guns oir infantry. Ill actual service it seldom occurs that tlie configuration of the ground admits of works being laid out with the exact dimensions and figures above described. These are intended to illustrate general principles capable of being modified and adapted to suit each particular case. Tiie plan of the work siiould be adapted : Ist. To tlie natural form of the site, taking advantage of all undulations to diminish the labor of construction f 2d. To tlie object in view; 3d. Tlie time available for construction and the number of men to form the garrison. The prolongation of all the principal lines of a work should be directed as much as possible on ground inaccessible to tiie ene- my, or at least where he cannot obtain an enfilade fire with his^ artillery. When circumstances permit, a field fort should be constructed with such care that the enemy will be forced to abandon an attempt to storm it and be obliged to resort to the method of regular approaches used in the attack of permanent works. To effect this, no ground around the fort within range of cannon should offer shelter to the enemy from its fire ; the ditches should be flanked throughout, and the relief be so great as to preclude any attempt at scaling the work. Approaches to it, particularly on the salients, should be obstructed by abattis,^ fraise, wire entanglements, &c. 613. Lines of works. {Figs. 2 to 5, Plate 58.) When it is nec- essary to hold for a time a line of considerable extent hj a force inferior to that which may be brought against it, the line should be fortified by intrenchments, consisting of a series of works laid out according to the foregoing principles. The kind of work for any particular position on the line will depend upon the nature of the locality it is to occupy and the manner iu which it will combine with those adjacent in securing mutual support throughout. Such lines are frequently from fifteen to twenty, or even thirty miles in length, extending over every variety of countr}', and in their construction call for the highest skill in military engineering. They are constructed, usually, either for the protection of important towns, cities, and depots; or to make secure the base of operations and lines of communications of an army manoeu- vering in the field; or, by stretching across peninsular regions, to restrict the theatre of operations of the enemy; or for sur- rounding and besieging a place ; or for the purpose of holding the enemy in position with a part of an army while the remain- der makes a flank or other strategic movement. The civil war LINES OF WORKS. 873 «of 1861-65 afforded numerous instances of each of these condi- tions. The same general principles apply to lines as to other field- works ; but from their great extent they usually receive only a slight relief, and the simplest angular figures are adopted for their plan. In laying them out, advantage should be taken of all the natural features presented by the position, so as to diminisli the labor of erecting artificial ones. The flanks of a line or position are generally weak points. When possible, one or both should rest on natural points of sup- port. A flank not so supported must be secured by strong works especially well garnished witli artillery. A point tliat has not a clear field of fire is a weak point, and should be strongly intrenched, so that the enemy may not have advantage of hills, ravines, or other shelters in approaching the line. Care should be exercised in determining the kind of artil- lery for such positions. The field of fire being contracted, long range is not of so much importance as ability to search behind the enemy's shelter, or to throw a great mass of projectiles in a limited time. Mortars, howitzers, and machine guns will be found serviceable. In establishing a line of works, the main object should be to cover every portion of the front within range with direct or crossfire. To accomplish this, all prominent points along the line are fortified, each with a work having a trace most suited to the conformation of that particular site. The most important of these should be inclosed works upon the bastion-front principle, and of considerable size, capable of enduring an independent attack. Smaller Inclosed works, such as redoubts and star forts, occupy the secondary points. Between the works thus located extend rifle-trenches capable of sheltering infantry. The line is there- fore composed of a series of works mutuall}'^ supporting each other and covering iiYfiry avenue of approach. The artillery, of which there should be an abundance, will naturally be placed in the works occupying the most command- ing and salient positions. These works should never be so far apart as to be out of mutual flanking range of the artillery with which they are armed. It is the duty of officers of artillery to cooperate with those of engineers in selecting the positions of the works that are to be armed with artillery, and to determine the kind and quantit}'^ to be placed in each. As infantry troops constitute the chief garrison of works of this nature, they will be required to construct them, leaving to 2the artillery the construction of magazines, embrasures, plat- 374 LINES OF WORKS. forms, and other accessories pertaining to their special arm^ Generally these works are thrown up very hastily, and often, when an immediate attack is apprehended; this, to a considera- ble extent, decides not only the nature of the works, but the parts of them that require the first attention. Subsequently, if time permits, they are strengthened, improved, and worked into better shape. As far as practicable, the line should be composed of inclosed works, for the reason that should the enemy concentrate and break through at any point, he will not be able to sweep the line to the right and left by taking it in flank and rear. To storm and capture each work in succession would be an operation too costly for him to undertake. It is advisable in most instances to have in front of the line, witiiin easy musket range, a line of small redans or lunettes at intervals of about 1500 j'^ards. Each of these should be capable of holding from one to two hundred infantry and four to six field-pieces. This line of outworks would form, as it wei'e, a species of picket line, keeping the enemy from closely observing and harassing the main line, and would constitute an advanced line of battle, against which the first shock of the enemy is par- tially thrown away, and he dare not attempt to neglect them; for an endeavor to penetrate through the intervals would expose his flanks to a close and deadly flank and cross fire. The redans being open towards the main line, could not be held if captured b}"" the enemy. A somewhat similar line of works should be established in rear of the main line. They should, however, have their gorges stock- aded or otherwise closed to prevent the enemy, should he suc- ceed in forcing his way through the main line, from obtaining easy possession of them by the rear. Sites for them should be selected with a view of obtaining from them a searching fire of the front line in reverse. This line of works, although appar- ently inert in rear, must be kept full^^^ armed and manned, ready to drive the enemj'' from anj'' part of the main line that he may succeed in obtaining possession of. Prominent salients in the main line are especially inviting to the enemy; behind these a second line should be prepared, so placed, if possible, that should the enemy obtain the main line he will be within musketry range of the second, and be forced with v/earied troops to undertake the capture of it. 614. An approximate estimate of the number of troops re- quired to man such a system of intrenchments may be obtained by allowing 300 men per mile for the first or redan line, 4000 for LINES OF WORKS. 375 the mtiin line, 300. for the rear line, and 1200 for reserves; mak- ing a total of 5800 per mile of actual lii^htiiig force. The amount of artillery required will depend upon such cir- cumstances as the kind employed ; the kind and quantity brought up by the enemy ; the nature of the country, and the quality of the troops on either side. From four to five pieces per thousand infantry is a fair estimate. To break a line of works the enemy would secretly concentrate as powerful a force as possible and assault some particular part of the line. As it would be impracticable to have at ever}' part of the line a force capable of successfully resisting such a con- centration, the probabilities are that he would succeed in his assault, if vigorously made. To dislodge him from any portion he might thus capture, it is advisable to hold strong reserves of both artillery and infantry at central and convenient points in rear of the line of works. One reserve of say 5000 infantry and 20 fleld-pieces for each four miles of line would make it almost impossible for an enemy of ordinary strength to hold any part of it that he might capture. Telegraphic communication should be established from one reserve to another and to every part of the line. This would insure a prompt cooperation of all the forces. In tracing field-works, care must be taken to direct, as much as possible, their faces upon ground least accessible to an enem}^ so as to reduce to a minimum the eff*ect of his enfilade. 615. When the importance of the case demands it and the means are available for carrying it out, lines of field-works some- times assume — as was the case during the rebellion — a semi- permanent character. These are laid out with great care and constructed witii skill and nicety; the.y are furnished with sub- stantial and commodious magazines and bomb-proof; the slopes are sodded and the revetments constructed for endurance. Works of this cliaracter are frequently armed with the heaviest classes of ordnance, the emplacement, care, and preservation of which, together with the ammunition therefor, will be governed by the same rules as for permanent works. 616. Tlie camps, parks, trains, hospitals, depots, &c., should be sufficiently far to the rear to be out of range from the fire of the enemy, and should have through communication to the vari- ous parts of the line b}'' means of well-constructed roads. These roads should be laid out in sucli manner as to be, as much as possible, out of view of the enemy. The horses of the artillery in the works, with their drivers, and all parts of the batteries not absolutely required for tlie efficient service of the guns, should be encamped, as above, in rear. The cannoneers, ofti- 376 DISTANCES — PARAPET. cers, and non-commissioned officers will invariably remain in the works, read}' for action at smy moment. . 61*7'. Distance of works frorn towns ^ cities^ fyc. Rifled artil- lery, of large calibre, is capable of doing- (rrent damage to towns, cities, dock-3'ards, and other objects of large extent, up to a dis- tance of five miles. A few pieces of enormous calibre have been constructed capable of throwing hnge projectiles to a distance of about nine miles. These are, however, exceptions, and as they can be made available only by means of a certain class of almost impracticable vessels, it is not necessary, at present, to embi'ace them in this consideration. Five miles being the limit within which the enemy must not be allowed to establish his batteries, the distance of defensive works within this limit will depend upon the character and power of the artillerj^ with which they can be armed. Heavy calibres are more capable of keeping aa enemy at a distance than small calibres, and rifles are superior to smooth-bores. About two miles is the limit of eflectlve range against ships of war, and beyond this distance It would be im- possible to prevent an enemy from carrying on operations by land; this, therefore, is the maximum distance that it is admis- sible to subtract from tiie live-mile limit of the enemy. In other words, if an enemy is able to bring heavy rifle guns against a large object, as a city or a dock-yard, works for its protection should be at least three miles distant therefrom. No snch area can therefore be surrounded and protected by a line of works of less extent than 18 miles ; generally It would be much more, depending upon the size of the city, town, or other objects. 618. Parapet. In fleld fortlflcatlons the main features are the covering masses of earth of which they are constructed, and which are intended to shelter the assailed from the view and flre of the assailant. When the covering mass Is so constructed as to afford the assailed a view and flre over the assailant's line of approach, it is termed a parapet; when intended simply as a screen or cover from the flre of the enemy, it is termed an epaul- vient; and when used to cover troops or guns from an enfllading flre on the flank or In the rear, a traverse. The simplest form of work is the rifle-trench or pit. {Figs. 1 and 2, Plate 59.) In this, the parapet Is formed by throwing the earth from a trench within to tlie front. The earth thus thrown up, togetiier with the depth of the trench, affords the desired shelter. The troops stand or squat in the trench and deliver their flre over the bank of earth in front. This method of intrenching affords the speediest means of obtaining cover, and is the one resorted to when troops are under flre, or when thej'^ intrench their camp PARAPET. 377 or position for a temporary stay. Rails, logs, in fact, almost anything at hand may be nsecl as a rough interior i-evetment for sustaining the earth. For artillery, the trench is made some- what wider than is necessary for infantry. 619. In the more elaborate class of field fortifications, such as the inclosed works previously mentioned, the earth to form the parapet is taken from the exterior, thus forming in front of the parapet a ditch which makes a formidable obstacle in the way of an assailant attempting to enter the w^ork by escalade. Fig. 3, Plate 59, shows the usual form of the profile of such an intrenchment in ordinary soil. B C D E F G, profile of parapet ; H I K L, profile of ditch ; M ]N" O, profile of glacis; A B, terre-plein, or parade; B C, ban- -quette slope, having a slope of one upon two ; C D, tread of the banquette, having a slope to the rear of two inches; D E, inte- rior slope, having a slope of three upon one ; E F, superior slope, having a slope of one upon four to six ; F G. exterior slope, having a slope of one upon one; G H, berm ;'H I, scarp, having a slope of about two upon one ; 1 K, bottom of ditch ; KL, counterscarp, having a slope of about two upon one; B, foot of the banquette slope ; C, crest of the banquette ; D, foot of the interior slope ; E, interior crest ; F, exterior crest ; G, foot of the exterior crest ; H, crest of the scarp ; I, foot of the scarp ; K, foot of the coun- terscarp ; L, crest of the counterscarp ; M, foot of the glacis ; N", <}rest of the glacis ; a 6, thickness of the parapet. The tread of the banquette is placed 4 feet 3 inches below the interior crest. The following table, giving the slope for various degrees of elevation, will prove useful. By referring to tables of ranges, and bearing in mind that the angle of fall of a projectile is always greater than the elevation of the piece, the table will also afford useful suggestions and data with reference to defilading works. In seeking protection from the fire of an enemy, either hy nat- ural or artificial cover, the drop of the projectile must be taken into accoinit. This depends upon the range, kind of piece used, and nature of fire employed. The table, furthermore, furnishes useful assistance, when studying defensive positions, as to locating batteries and deter- mining the kind of artillery to be placed at the various points for reaching ground that may be occupied by the enemy, and which is sheltered by undulations or by timber growth from view from the work. In connection with this, see^ar. 650 and tables of ranges for the 8-inch and 100-pounder rifles. t 878 DITCH. Angle. Rise. Angle. Rise. Angle. Rise. Angle. Rise. Deg. One on. Deg. One on. Deg. One on. Deg. One on. 1 57.3— 9 6.3+ ]7 3.2 + 25 2.1 2 28.6 + 10 5.7+ 18 3.0+ 26 2.0 3 19.0+ 11 5.1+ 19 2.9— 27 1.9 4 14.3— 12 4.7 + 20 2.7+ 28 1.85 5 11.4+ 13 4.3 + 21 2.6 29 1.80 6 9.5- 14 4.0+ 22 2.5— 30 1.75 7 8.1+ 15 3.7+ 23 2.3+ 8 7.1+ 16 3.5— 24 2.2 The dimensions of the parapet will depend upon the kind of eartli used and tlie time and means that can be employed in its construction, together with the time that the work is to remain occupied, and, finally, with the time and means the enemy can dispose of in the attack, and the degree of resistance the work should offer. The relief, which is the vertical hei<>;ht (E a> of the parapet above the terre-plein, should not be less than 8- feet, and it will be seldom necessary or expedient to exceed 12 feet. Its thickness, which is the horizontal distance (a b) be- tween the interior and exterior crests, is regulated by the kind of earth u.sed and the kind of attack it is expected to meet. If it is to resist artillery, the thickness is that given in par. 596, in which the minimum is laid down at 14 feet. The relief of a work, or of any part of a work, is its height above the ground on which it stands. The command of a work is its elevation with reference to the surrounding country, especiallj'' that within striking distance, which may be occupied by an enemy. 620. Ditch. The dimensions of the ditch should be i-egulated to furnish the earth for the parapet. To present a respectable obstacle to the enemy, its depth, however, should not be less than 6 feet, nor its width at the top less than 12 feet. For approxi- mate purposes, the dimensions of a ditch to supply earth neces- sary for a given parapet may be obtained by assuming the depth of the ditch and dividing the area of the profile of the parapet by it to obtain the width. In turning the salients, keeping the dimensions of the ditch the same, there will be an excess of earth, — a circumstance which may be taken advantage of by making the parapet thicker in these parts. Due allowance must be made for this when lay- ing out the work. The salients should always be the thickest and strongest. 621. Tracing. In laying out the figure of a work on the SOD REVETMENT. 379^ ground, which operation is called tracing^ the interior crest is taken as the governing' line ; all other lines are laid off with ref- erence to it. Profiling. The trace being laid otf and marked by stakes at the angles, profiles of the parapet, [Fig. 1, Plate 60,) constructed of strips of light wood, are set up at the angles, and at other points along tlie parapet where long stretches of the latter occur. The method of establishing these profiles will readily suggest itself. When strips of wood are not easily obtained, stout cord may be used instead, the cord being attached to the uprights at the points where the strips of wood are or would be nailed. When a sufficient portion of the profiling is completed, work- ing parties are set to work excavating the ditch and forming the parapet. The latter, as the work progresses, should be well rammed. If the soil is stony, the vegetable mould on tiie sur- face should be removed, and reserved to form the top of the par- apet. Tills should always be free from stones to a depth of at least three feet, to prevent injury to the troops from tlie eff'ect of shot striking and scattering the pebbles and fragments. Those portions of an eartli-work within effective range of the enemy's artillery, and upon the endurance and integrity of which depend the support and safety of valuable batteries or magazines, should be made strongest by additional thickness and height. The material and workmanship should be of the best quality. It is almost impossible to make a breach in a work constructed of sand of sufficient thickness to prevent penetration through and through it and having flat slopes towards the breaching batteries of the assailant. In such cases the sand displaced by successive shots falls back again and again within the area- attempted to be breached. 62^. Revetments. A revetment consists of a facing of stone, wood, sods, or other material to sustain an embankment which has a slope steeper than the natural slope of the particular kind of eartli used. In field-works, revetments are used only for the interior slope of the pai'apet and for the scarp. For the first, sods, palisades, fascines, logs, gabions, and plank are chiefly used; and for the last, timber. 6!23. Sod revetment. Sod-work forms a strong and durable revetment. Tlie sods should be cut from a well-clothed sward, with the grass of a fine short blade and thickly-matted roots* If the grass is long it should be mowed before the sod is cut^ ^80 FASCINE REVETMENT. The more tenacious the soil the better will be the sods. Those cut from sandy localities are of but little value. Sods are of two sizes : one, termed strechers^ are 12 inches square and 4^ inches thick ; the other, termed headers, are 18 inches lonj^, 12 inches broad, and 4^ inches thick. The sod revetment {Fig. 2, Plate 60) is commenced as soon as the parapet is raised to the level of the tread of the banquette. A course of sods is then laid, either horizontal or a little inclined from the banquette. The course consists of two strechers and one header alternating, the end of the header being laid to the front; the grass side is laid downwards, and the sods should protrude a little beyond the line of the interior slope, for the purpose of trimming the course even at top, before laying an- other, and to make the interior slope regular. The course is firmly settled by tapping with a spade each sod as it is laid, and the earth of the parapet is packed closely behind the course. A second is laid on the first so as to break joints with it. The top course is laid with the grass side up, and in some cases pegs are driven through the sods of two courses to connect the whole more firmly. When cut from a wet soil, the sods should not be laid until they are partiall}'' dried; otherwise they will shrink a,nd the revetment crack in drying. In hot weather the revet- ment should be watered frequently until the grass puts forth. Sod revetment, on account of its durability and freedom from splinters, is the best of all revetments. Log revetment. {Fig. 3, Plate 60.) This revetment is made of trunks of small trees or saplings laid horizon tall}'^ one on the other and supported by posts set into the banquette. At fre- quent intervals tie beams are dovetailed between the logs, and, extending six or eight feet into the parapet, are secured to horizontal anchoring logs. For intrenchments hastily thrown up, this is the most usual form, rails or timber of anj?^ kind being used. 6124. Fascine revetment. A fascine {Fig. 4, Plate 60) is a bundle of twigs closely bound together. There are two sizes of fascines : one size is 9 inches in diameter and about 10 feet long; the other, which is generally termed a soucisson, is 12 inches in diameter and 20 feet long. It is chiefly used for the revetments of batteries. To make a fascine straight twigs are selected, between the thickness of the little finger and thumb, — the longer the better. They should be stripped of the smaller twigs. A support, term- ed a fascine-horse, {Fig. 5. Plate 60,) is put up by driving two stout stakes obliquely into the ground about two feet, so as to «cross each other about two feet above the ground, where they GABION REVETMENT. 381 are flrml}^ lashed together. As many of these supports as may be required ai*e put up in a straiglit line, about 18 niches apart. Tlii.^ forms the horse, on which the twigs are laid to be bound together, A machine (C D) termed a fascine choker is formed of two stout levers about 5 feet long, connected near theii- extremities by a chain or strong rope, which must be long enough to pass once around the fascine and be drawn tight by means of the levers. The twigs are laid on the horse with their laige and small ends alternating; the choker is applied to bring them together, and they are bound by wire, or by withes made of tough twigs, properly prepared by twisting over a blaze, so as to render them pliable. The ties are placed 12 inches apart, and every third or fourth one should be made with an end about three or four feet long, having a loop at the extremity to receive a stake through it. This stake is termed an anchoring stake^ its object being to secm'e the fascine firmly to the parapet. To form the revetment, the first row of fascines is imbedded {Fig. 4, Plate 60) about half its thickness below the tread of the banquette, and is secured by means of the anchoring stakes, and also by several stakes driven, through the fascine itself about 12 Indies into the earth. The knots of the ties are laid inside, and the earth of the parapet is well packed behind the fascine. A second row is laid on the first, so as to give the requisite interior slope ; it should break joints with the first row, and be connected with it by several stakes driven through them both. The other rows are laid with similar precautions, and the parapet is usually finished at the top by a course of sods. 625. Post revetment. {Fig. 6, Plate 60.) This is construct- ed of posts from 4 to 6 inches in diameter, cut into lengths of 5.5 feet, and set with proper slope, in close contact, in a trench two feet in depth, at tlie foot of the breast-height. The tops of the posts, if not alreadj"- so, are sawed off level, to receive a horizon- tal capping piece, which is spiked on. Anchor ties are dove- tailed into the cap and secured to an anchor log imbedded in tlie parapet. On top of the cap are laid several courses of sods, rais- ing the interior crest to the proper height. With a good quality of timber this revetment is durable. It is easily constructed, and next to sods is the best. 6:26. Gabion revetment. {Fig. 7, Plate 60.) The gabion is a basket of a cylindrical form, open at each end. Its height is usually 2 feet 9 inches, and diameter 2 feet. To form a gabion, a directing circle is made of two hoops, the difference between their radii being such that, when placed con* ^82 PLANK REVETMENT — SAND-BAGS. -centrically, there shall be about If inches between thera. They are kept in this position by placing small blocks of wood between them, to which they are tied with pack-thread. The directing circle is placed on the ground, and seven or nine stakes, about 1 inch in diameter and 3 feet long, are driven slightly into the ground between the hoops, at equal distances apart ; the directing circle is then slipped up midway from the bottom, and tied in that position. Twigs about half an inch in diameter, and as long as they can be procured, are wattled between the stakes like or- dinary basket-work. When finished to within about 2 inches of the top, the gabion is placed with the other end up, the directing circle taken off, and the gabion completed to within 2 inches of the other extremities of the stakes. The wicker-work at the two ends is secured by several withes, and the ends of the pickets are sharpened. The gabion is then ready for use. To form the revetment, a fascine is first laid partly imbedded below the tread of the banquette; {Fig. 4^ Plate 60;) the gabion, which is placed on end, rests on this, so as to give it the requisite slope ; it is then filled with earth ; others are placed in like man- ner, and the parapet is raised behind them ; another fascine is laid on top, and in some cases two. In making gabions, iron hoops, similar to barrel hoops, may be used instead of- wattling. The number of stakes should be increased to eleven or thirteen. Gabions made either of wattlings or hoops are not good for holding dry sand. Sheet-iron is preferable to either iron hoops or brush for ga- bions. For this purpose rectangular sheets of suitable dimen- sions to form cylinders of the same height and diameter as the ordinary gabion, are prepared with three holes punched near to and parallel with the shorter sides of the sheets. These are to secure the ends with wire when the sheet is bent into the cylin- drical form. The advantages of this description of gabion are greater strength, lightness, and durability than either of the other two, offering great facility for transportation, and resist- ing better the blast of guns when used for reveting the cheeks of embrasures. Galvanized iron is less liable to rust than plain iron ; when not galvanized, the gabions should be lacquered with coal-tar. 627. Flank revetment. This may be made by setting stout posts of scantling about 3 feet apart, 2 feet below the tread of the banquette, giving them the same inclination as the interior slope. Behind these stakes boards are nailed to sustain the ^arth. The posts should be securely anchored into the parapet with wire and stakes. 638. Sand-bags are sometimes used for revetments when SCARP REVETMENT. 383 other materials cannot be procured; though their object in most agazine will depend upon the number and calibre of pieces in the work and the number of charges to be kept for each. This data being known, the amount of storage room required will be de- termined by allowing 5780 cubic inches for each barrel contain- ing 100 pounds of powder. Projectiles and cartridges for siege and field guns are put up in boxes, as explained in par. 565, and are stored in magazines kept especially for this kind of ammunition. Each box of siege- gun ammunition contains four projectiles and four cartridges, and measures about 2950 cubic inches. Each box of field-gun anunnnition contains ten projectiles and cartridges, and meas- ures about the same. From this it is easy to obtain the storage capacity required for any amount of these kinds of ammunition. The dimensions of the interior of the magazine should be so regulated as to entail no unnecessary loss of space in storing its contents. The exterior dimensions of a powder barrel are : Length, 20 inches ; diameter at bilge, 17 inches. With the bar- rels stored in the usual way, on the side, {Fig. 1, Plate Q^.) a magazine 6 feet 6 inches high would afford space for four tiers, leaving 8 inches on top for handling room. A magazine 10 feet wide will give room for four rows, leaving 40 inches for passage- way ; therefore each 17 inches of length of a magazine 10 feet wide by 6.5 feet high will contain 16 barrels. A magazine of this height and width and 30 feet long would store 400 barrels and leave a space of about one yard in width, extending across it, at the entrance. At the rate of 100 rounds for each 15-inch gun, a fair allow- ance for such guns in field-works, a magazine of the foregoing dimensions will give storage for a supply of powder for four pieces. The number of rounds per gun should increase as the calibre diminishes. It would, however, seldom be necessary to have more than 300 rounds for any calibre above 100-pounders. An ordinary packing- box containing the number of rounds before specified measures, in exterior dimensions, 19 inches in length, 13.5 inches in width, and 11.5 inches in height. These dimensions allow the boxes to be compactly packed in a maga- zine of any ordinary shape, and it requires only a small calcula- tion to determine the storage room required for any given num- ber of rounds for guns of these calibres. It is best not to exceed, for any one magazine, the dimensiona^ STORAGE MAGAZINE. 391 above laid clown, Damely, 30 by 10 by 6.5 feet. When greater storage room is required, two or more should be constructed. Precautions to secure drainasfe are of the utmost importance. Generally the ground is sufficiently undulatmg to effect this by means of a covered di-ain leading from the bottom of the maga- zine. Where this is not practicable, the bottom of the excava- tion must be formed so as to collect the water at one point, whence it may be removed by pumping or bailing. Figs. 1 and 2 illustrate the best method of constructing a stor- age magazine. The sides of the interior of the magazine are formed of 12-inch logs, either square or round, placed verticall}'' hi juxtaposition, and resting on aground-sill. These are capped on top by a 2-inch plank, a strip of the same being spiked on within the cap. The roof is formed of 15-inch logs, laid across, in juxtaposition, each having a shoulder of 3 inches to fit it to the cap and inside strip. Longitudinal logs with varying diame- ters are laid on these, so as to give a proper pitch to the roof. Earth is solidly packed upon the top and between the roof logs, receiving the proper slope for the roofing boards. These boards, carefullj^ joined, are laid on in two thicknesses, each being covered with a coating of asphalt or coal-tar; upon these boards rest the covering of earth. The flooring is of joists and boards. The sides of the magazine are surrounded with an air-chamber formed of inclined logs supported on a ground-sill and resting against tlie top logs; these are placed at tln-ee or four feet apart, each one being braced at the middle to resist flexure from the pressure of the earth. The air-chamber is covered in by saplings laid upon each other horizontally. Ventilators are placed between the magazine and the air-chamber, near the top, and also between the latter and the external air, the two not being opposite, and the usual precautions to guard against sparks, by covering the mouth with wire cloth or perforated tin, are taken. The whole is covered with earth, the thickness of which will depend on tlie character of the enemy's artillery. In no case should it be less than 14 feet on the exposed side; 10 feet will be sufficient for the other sides and the top. The entrance may be either upon an end or side, depending upon how the magazine has been located with reference to the enemy. In all cases the entrance must be on the side from the enemy, and should be secured by a bomb-proof covering. The magazine chamber should, if prac- ticable, be placed at least two-thirds of its lieight below the sur- face of the ground. The ammunition is stored and cared for as explained in par. 569. In this and all similar structures railroad iron is a highly serv- 392 SERVICE MAGAZINES. iceable material for roofing, the bars being laid in juxtaposition in place of the logs before mentioned. Service magazines. The size of these will depend upon the number of rounds it is desirable to have ready for immediate use ; usually, twenty rounds for sea-coast guns, and from fifty to a hundred for those of smaller calibre, will be sufl3cient. The capacity of the magazines to hold this amount or any other that may be fixed upon will be determined by the rules just given. If the magazine is to hold barrels, it should be 6.5 feet high and 7.5 wide ; this will accommodate four tiers of three rows, leaving a passage-way of 30 inches. The length will depend upon the number of barrels, and this will be governed by the number and calibre of pieces to be provided for ; generally, 15 feet will be ample. A magazine of this description is usually constructed of coffer- work. A coffer- work is formed by making frames {Fig. 1, Plate 66) cor- responding in dimensions with the cross section of the magazine ; each frame is composed of two uprights, termed stanchions, and a cap and sill of stout timber or scantling, not less than 6-inch. The cap and sill pieces are slightly notched to fit tlie stanchions, and all seciu'ed togethei* with nails or spikes. These frames are placed upright and parallel to each other, about 2 feet apart; they are covered on the top and sides with 2-inch plank, termed a sheeting. The magazine, otherwise, is constructed as in the last case. A very good magazine, and one easiest of construction, is made of logs notched together at the corners after the fashion of a log cabin. {Fig. 2, Plate 66.) Other logs are laid in juxtaposition across the top, and the whole covered over with earth. This is the most substantial for those placed in traverses. For field and siege pieces the magazines are not required to be so large. A height and widtli of 6 feet with a length of 12 feet will generally be sufiicient. Magazines of this size may be made as just described, or they may be made of gabions. {Fig. 3, Plate 66.) When the latter are used, a hole is usually dug in the ground to form part of the magazine; the gabions are placed in three rows, side by side, around the hole, and are filled with earth. The top is formed of timbers laid across in juxtaposition and covered with fascines, the whole being covered with a proper thickness of earth. The bottom is covered by a fl.ooring of joists and boards, a shallow ditch being left under the flooring to carry any water to a drain outside. This, at best, is but an inferior method of constructing a magazine. TRAVERSES. 393 Entrances to maoazines must always be on the side from the <>neiny, and protected by a splinter-proof shelter large enough to afford easy access to the door. Splinter-proofs are usually constructed of scantling or trunks of trees cut into suitable lengths and placed in an inclined posi- tion over the magazine door. {Fig. 4, Plate 66.) The timbers are placed side by side, and covered with at least two feet of •earth or sods. To prevent rain from percolating through the earth on top, the magazine is covered with a paulin laid on the earth and secured with pickets. To prevent rapid decay of the paulin, it should be payed with a mixture of tar and grease boiled to- gether — about two parts of tar to one of grease ; this composi- tion is applied to both sides. In dry weather the paulin should be removed to let the earth dry. Boards, bark, or shingles may be used instead of paulins. Adjoining or near the service magazine is a tilling-room, in which the powder barrels are opened and the cartridges made up and the shells tilled. A room 10 feet square hj 6J feet high will generally be sufficiently large. It is constructed in the same manner as the magazine, and is fitted with shelves, &c., for the convenient keeping of primers, fuses, implements, and other small articles required in making up cartridges and preparing shells. While being convenient to the magazine, it should be so sit- uated that an explosion taking place in it will not communicate tire to the magazhie. Fig. 2, Plate 65, represents the ground plan of one form that may be adopted. The powder is carried from the magazine to the filling-room in canvas or leather stretchers, and only in such quantities at a time as may be necessary for keeping the pieces served. 63§. Traverses. Those which are placed between guns or on their flanks to cover them from an enfilade fire, are usually termed gabionades. To form a gabionade, gabions are placed in a row {Fig. 5, Plate 66) side by side, inclosing a rectangular space of about 15 feet in width from out to out, and about 24 feet in length, per- pendicular to the parapet. A second row is placed within this and touching it, and a third row inside of the second. The area thus inclosed is filled in with earth to a level with the top of the gabions. Six rows of large fascines are next laid on the gabions to support a second tier consisting of two rows. The second tier is filled in like the first, and the earth is heaped up on top. Four rows of large fascines are placed on these to support a third •consisting of one row, making the gabionade nearly 12 feet 394 BOMB-PROOF SHELTERS. high. The ends are hiclosed by filHng in with gabions, as for the sides. A passage-way of about two feet is left between the end of tlie traverse and the parapet. This space ma}' be roofed over with logs and earth to form a cover in which the cannon- eers may shelter themselves against fragments of siiells. Splinter-proof traverses xn^j be made by placing two thick- nesses of gabions side by side filled with earth, with a second tier of one thickness on top. When a service magazine is to be placed in a gabionade, the rows of gabions are set farther apart, and the excavation for the magazine is made between them. The chamber of the magazine is constructed in one of the ways heretofore described. t 639. Bomb-proof shelters. These are for the protection of the troops when not on duty. They should be located on the parade, convenient to the pieces to be served, yet not so near as to interfere with the defense. They are usuall}'" constructed in half excavation of logs built up like a log house, or of a frame- work in the manner shown in Fig. 1, Plate 67, the exterior side being of heav.y logs placed vertically in juxtaposition, rest- ing on a ground-sill and capped at top. Parallel to this is an- other row, forming the other side, which may also be placed side \)y side or at short intervals apart, and capped like tiie outside^ row. The roof, consisting of heavy logs laid in juxtaposition and covered with thick boards joined, rests on the capping, the whole covered over on the side of the enemy with earth to a depth of at least 14 feet from the wood-work. To prevent this mass of earth from pushing the structure over to the rear, one in every two or three of the roof-logs are cut of sufficient length to extend about 8 feet beyond the front of the wall, and dove- tailed to a longitudinal log held in position by vertical posts, the anchor-log being sufficiently covered with earth to protect it from injury by shot from the enemy. These bomb-proofs are made to serve the purpose of traverses, and are frequently arranged with a staging or gallery along the rear side for the accommodation of infantry, who deliver their fire over the top, arranged for this as a parapet. In all interior arrangements, system and regularity should be observed from the first ; otherwise the work will grow into a labyrinth of confusion greatly opposed to efficiency and comfort. 64®. Splinter -proofs made after the foregoing plan, but smaller, may be placed against the parapet between the guns. These not onlj^ afford slielter for the men, but give a place to- keep implements and a few rounds of ammunition readj^ for immediate use. Another convenient form of splinter-proof may BATTERIES. 395 be made b}^ leanino: logs or railroad-iron bars against the sides of traverses and covering them over with earth. Works exposed to anything like constant and protracted artil- lery fire, shonld be provided with bomb and splinter proof shel- ters sufficient to comfortably lodge the entire garrison. This is made more necessary now than formerly, from the very great range and searciiing power of modern artillerj^ which makes it impossible for a garrison to obtain rest without going to too great a distance from the work. As a general rule, troops should, for sanitary reasons, be quartered as much as possible outside of the works. Tlie importance of protecting guns and their carriages with traverses and epaulments bears an increasing ratio to the size of the piece. Formerl}', when guns were comparative!}'' light, works were garnished with them in great numbers, and the fact of having a few of tliem disabled was of but little consequence ; it required but simple appliances and only a few hours to replace them by others. With modern heavy artillery, it is impracticable to have many pieces in a work, and when one. is disabled it requires days instead of hours, and the employment of much machinery and labor, to replace it. 641. Batteries. The field-work that artillery troops are most frequently called upon to construct is the battery. This may be for one piece or for several. Fig. 2, Plate 67, represents a bat- tery for four siege-pieces. In this instance, tlie parapet (A) is made of earth taken from the front, thus forming a ditcli (C). To protect the pieces (XX XX) from flank tire, the parapet is continued around on one or both ends, forming epaulments (BB). The guns are in pairs, separated by a traverse (D). The interval between the axes of the embrasures of each pair is 16 feet for guns on travel- ing carriages, and from 18 to 22 feet for sea-cpast guns. Be- tween the two middle pieces, this distance is increased by the thickness of the traverse, generally about 15 feet. Tlie entire length of the interior crest of the parapet, from a to 6, will there- fore be 79 feet. This and other giv^en dimensions are not abso- lute, but indicate tlie method of obtaining the data necessary for laying out an?/ battery. The length of the flank epaulments will depend upon the direction of the enemy's fire; in all cases, it must be sufficiently great to give full protection to the whole interior from an enfilading fire; generally it would be about 24 feet. The thickness of the parapet and epaulments will depend' upon tlie power of the artillery they are expected to resist.. 396 BATTERIES. (See par. 596.) The details of the various parts are the same as heretofore given. Wiieii the earth is thrown up from the rear to form the para- pet and epaulments, the work is termed a sunken battery. The ditch (C) is then dispensed with. In many instances a ditch is of but little importance, and for economy of labor the earth may be taken from both front and rear. Embrasiu'es for guns firing with great angles of elevation may receive a counter-slope, giving the sole nearly the same inclina- tion from the sill upwards as the least angle of elevation uuder which it may be required to aim the piece. {Fig.. 4!^ Plate 61.) Batteries for even the heaviest pieces may be constructed on marshy ground by laying a grillage of timber over the surface and building up the parapet on it with sand-bags. To prevent the parapet fi-om settling over towards the fnmt, the grillage should extend several feet beyond it in that direction. In or- der that the platform of the piece may not be moved from its true horizontal position by any settling of the parapet, the space to be occupied by it is inclosed with strong sheeting piles. In this inclosed space several la5''ers of fascines are laid, crossing each other at right angles; on these earth or sand is rammed, and the platform laid in the usual manner. If sand is used on top of the fascines, two or three thicknesses of paulins should be spread over them to hold the sand. Magazines in such locali- ties must, of necessity, be entirely above ground, and supported on grillage in the same manner. 64*2. Batteries are classified according to their construction, use, and armament, as follows: Covered battery., intended for a vertical fire and concealed from the enemy ; breaching battery^ intended to breach the works of the enemy ; Joint batteries., unit- ing their fire against the same object ; counter-battery, one bat- ter}'^ opposed to another; cross-batteries., forming a cross-fire on an object ; oblique battery forms an angle of 20 degrees or more with the object against which it is directed, in contradistinction to direct battery ; raised battery., one whose teiTC-plein is elevat- ed considerably above the ground; sunken battery., where the sole of tlie embrasure is on a level with the ground, and the platform consequently sunk below it ; enfilading battery., when gthe projectiles sweep along a line of troops, a ciiannel, road, or part of a work; liorizontal battery., when the terre-plein is that lOf the natural level of the ground; open battery., without epaul- ment or other covering — wholly exposed ; indented battery, or bat- .terj'^ a cr^mailli^re., one constructed with salient and reentering angles for obtaining an oblique fire as well as a direct fire, and sto afford shelter from the enfilade fire of the enemy; reverse baU WIRE ENTANGLEMENTS, ETC. 397 tery^ that which fires upon the rear of a work or Ihie of troops ; ricochet battery^ that whose projectiles, beino^ fired at low eleva- tion, graze and bound along without burying themselves ; masked' battery^ artificially^ concealed until required to open upon the enemy ; mortar batteries^ gun batteries^ &c. 64t$» Mortar batteries. These have the principal features of batteries for guns. It is desirable that they should be located where good views of the enemy's position may be had ; this, in order that the gunner may himself see the eflfect of his shot, and not, as is too frequently the case, have to depend upon the im- perfect report of a distant observer. For siege mortars, the platforms are placed the same distance apart as for siege guns, viz., 16 feet ; for sea-coast mortars, tlie distance is the same as for sea-coast guns, viz., 18 to 22 feet. They are usuallj'- placed in pairs, with traverses between each set of pairs. Embrasures are not required, and as the platform must be at such distance from tlie parapet tliat the blast will not injure the interior crest, it is not necessary to revet the interior slope, the earth being allowed to assume its natural slope. The siege-mortar platform furnished for field purposes is too light to sustain much firing. For fixed batteries, they should be constructed of heavy timbers, and, to insure anything like accu- racy in firing, nuist be both level and stable. The sea-coast platforms {par. 229), when properly laid, are in every respect effi- cient. A good kind of raiT platform may be made by using two pieces of timber {Fig. 4, Plate 67) 12 to 15 inches square and 9 feet long for the rails, to which planks 2 or 3 inches thick and 8 or 9 feet long are spiked. The rails are parallel, and have their centres 28 inches apart for the 10-inch mortar, and 22 inches for the 8-inch. A pit is dug large enough to receive this struct- ure, and the bottom being made perfectly level, it is placed in it with the planks down. Earth is filled in on top of the plank- ing. This Idnd of platform is particularly well adapted to sandy localities. If the mortar is intended to be fired in various direc- tions, a sufficient number of rails are used to extend over the whole surface, the planks being spiked to all of them. 644. Wire entanglements^ abattis., S^c. Every approach which an enemy might use to reach a work, should be so ob- structed as to keep him as long as possible under a close fire of musketry. The best thing for this pui-pose is wire entangle- ment, made by planting stout stakes, {Fig. 5, Plate 67,) about 3^ feet long, 2 feet in the ground and 7 feet apart, in quincunx order and in three or four lines. Around the tops of these stakes, at from 12 to 18 inches from the ground, in notches pre- pared for the purpose, telegraph or other strong wire is securely ^98 TORPEDOES. wound, extending from one stake to another. This obstacle is rapidly made, is difficult to remove, and can be injured but little by the fire of the enemy. 645. Ahattis is formed of the large limbs of trees, or of small trees themselves; the small branches are chopped off and the ends, pointed and interlaced, are presented to the enemy. The large end of the limb or tree is secured to the ground by stakes. Obstacles should be in two or more lines, and not too close to the work ; the first line should be about 100 yards in front, and the others beyond, at about 50 yards intervals. 646. Torpedoes^ if used, would be placed in these intervals. These weapons depend for their utility more upon their deter- ring than upon their actual destructive power. Men who will march bravely up through a blaze of musketry will wallc timidly overground in which they suspect the hidden mine. Torpedoes maj^ be simply shells charged with powder and slightly buried in the gi'ound ; or they may be wooden boxes, kegs, or any other vessel capable of holding and keeping dry a charge of powder. Shells produce their effect from their fragments, and likewise, if large, from the blast of the explosion. Charges otherwise in- closed produce effect only by the blast ; consequently the greater the quantity of powder the greater will be the effect. The chief difficulty in planting torpedoes is in the arrange- ment for igniting them at the proper moment. This may be done by electricity, as for submarine mines, or by a self-acting device whereby the charge is exploded by the tread of an enemy passing over it. The device used by the Russians at Sebastopol is perhaps the best of many that have been tested. The case consisted of a cubical wooden box {a b c d^ Fig. 1, Plate 68) large enough to contain a charge of 10 to 20 pounds of powder. This box was contained in another box (ABC D), leaving a space between of about 2 inches, which was filled with pitch, render- ing the powder in the inner box secure from moisture. The top of the exterior box was placed 6 or 8 inches below the surface of the gi'ound, and on it rested a board about the size of the top ; this board stood on four legs of hoop-iron about 4 inches high. The top of this board was near the surface of the earth, and covered slightl}'^ so as not to be perceived. On any slight press- ure upon the board, such as a man treading upon it, the hoop- iron supports yielded and the board came in contact with a glass tube (X) containing sulphuric acid ; the tube breaking liberated the acid, which came in contact with a priming of potassa chlo- rate and loaf-sugar within the box, causing instant combustion and, as a consequence, explosion of the powder. The glass tube 18 placed within another of lead, tin, or other metal which bends MANTLETS. 399 readily, yet strong enough to afford a certain degree of protec- tion to it. The metal tube conducts the acid to the interior after the ghiss is broken. Instead of the interior box, a shell filled with powder may be used. Other devices for exploding tlie •charge are frequently employed. They are constructed upon the principle of a plunger striking upon fulminating composi- tion, but these are diflScult to construct so that moisture will not enter and destroy either the fulminate or charge. When torpe- does are planted, the position of each one should be so marked as to be known to friend, but not to the enemy. They should not be planted in front of any work from which sorties are to be made. They are useful along beaches to prevent the enemy from landing. 647. Mantlets. A mantlet is a shield placed over the mouth of an embrasure to prevent musketry bullets and fragments of shells from flying through and injuring those serving the piece. A hole in the lower part allows the muzzle of the piece to pass through into the embrasure when it is to be fired. The size of these openings will depend upon the dimensions of the piece. Rope is the best material for constructing mantlets. The usual size of a mantlet is 5 feet high, 4.5 feet across, and 4 inches thick. For siege guns the opening is 1.6 feet high by 1.3 feet across. Three-inch rope is a suitable size ; it is laid in three or five thick- nesses, each of the two outer layers being in one piece bent ver- tically. {Fig. 2, Plate 68.) The inner layers are bent and laid horizontally, and the whole well tied together. The mantlet is hung on a horizontal pole supported by forked uprights set in the ground, on each side of the embrasure, at the foot of the interior slope. The elasticity thus aflbrded by the supports greatly increases the resistance of the mantlet. A small hole or filit is pierced in the mantlet to allow the piece to be aimed. Mantlets of this size weigh about 400 pounds. A small ring mantlet of rope {Fig. 3, Plate 68) placed upon the chase of the gun is sometimes used. When rope cannot be obtained, one of similar shape may be made of w^ood. Mantlets may be made of wood or of iron, or of wood and iron combined. Those of the latter kind furnished for the siege of Yorktown were made of two thicknesses of ^incli wrought- iron spiked to 3-inch oak plank. On the head was a 2-inch siquare iron bar riveted to the edge of the iron plates, against which the oak planks abutted. The ends of this bar projected Q inches, and were rounded, serving as supports to rest upon upright stakes or timbers standing against the interior slope of the parapet. 400 GUN-SHIELDS — BLOCK-HOUSE. Mantlets, when supplied at all, are supplied by the Engineer Department. 64§. Gun-shields. Wlien railroad iron can be obtained,, shields, with embrasures in them, can be made as represented in Fig. 1, Plate 69. One thickness of iron is sufficient protection against projectiles from field guns, two from siege guns, and four from pieces of the 8-inch rifle class. The same material may be used for constructing field case- mates. Block-house. {Fig. 2, Plate 69.) This is a species of small redoubt, usually built of wood, and intended for an isolated point wiiich can be approached by stealth or stratagem, requir- ing the garrison to be constantly on tlie aleit, with their arms in hand. It is at once a house and a fort. They are usually con- structed for tlie defense of bridges against cavalry raids. Tliey are also used in the Indian countrj'^ as a defense against savages,^ in which case the}^ are usuall}'- placed at opposite angles of a stockade for flanking purposes. They are made 10 feet high in the clear, and from 20 to 25 feet square. Logs 16 to 18 inches in diameter are used; these are hewed on two sides and placed together, their hewed sides in contact. They may be built up in the manner of a log-house, but it is preferable to set them up vertically. The roof is made of heavy logs extending over the walls about 18 inches on all sides. On these logs a covering of earth is placed 4 feet thick at the crown and running down to a depth of 6 inches at the eaves. This earth is thoroughly rammed, and in it are imbedded pur- lins, upon which is constructed a roof of boards or shingles. Loop-holes for musketry are cut through the walls, the splay being on the inside., and the height above the floor 8 feet. A banquette of plank 3.5 feet from the floor and 6.5 feet in width is carried around the interior ; this serves also as a substitute for bunks. Machine guns are eminently adapted for block-houses ; next to these are howitzers, or other pieces effective with canister. Each house should be supplied with two or more such pieces, embrasures for which are cut so as to sweep the main avenues of approach. The throats of the embrasures are closed when not in use by heavy timber doors, barred on the inside. The embrasures are cut at a proper height from the floor for the car- riage used, and the banquette made in movable sections behind each embrasure. Around the outside is dug a V-shaped ditch, the earth being thrown up against the sides of the house, at an angle of 45 de- grees, as high as the soles of the loop-holes. The cheeks of the BLOCK-HOUSE. 401 embrasures through this bank are of hewn timber, and a roof of the same is laid across to sustain the slope just mentioned. A small magazine is placed below the floor. A well-constructed abattis and wire entanglement should surround the work at a distance from it of about 100 yards. A block-house thus con- structed is pretty secure against any artillery accompanying cavalry raids. The general idea of a block-house may be utilized in the con- struction of bomb-proof covers or casemates for guns in field- works, 26 wnvt mm^* ATTACK AND DEFENSE OF POSITIONS. 649. In the attack upon intrenched positions, the points Tegarded as the most advantageous are those in which the gen- eral combination of the defensive line forms a salient with ref- erence to adjacent parts. Such positions can receive but little support from collateral portions, and can, to a greater or less degree, be enveloped by a line of intrenchments of much greater extent than itself, affording opportunities for establishing enfi- lading and other batteries, the fire from which will be conver- gent upon the point of attack. Fig. 3, Plate 69, illustrates some of the advantages to be gained by the selection of a salient as the point of attack. The full line represents the trace of a regular work following theoretically tlie general contour of the salient to be attacked. An inspection of the figure shows that A, upon the prolongation of the face E F, will be the best possible position for the attacking artillery ; as from this position the projectiles, after grazing the parapet at the point E, will rake the entire face E F. It is quite impos- sible to protect such a line by traverses and at the same time maintain a stout defense against a front attack. From the point B, within the prolongation of the face, the latter is struck in reverse under so small an angle as to weaken but slightly the advantage of enfilade. It becomes less efficient as its distance from the prolongation of the face is increased. The next most advantageous position is at C, on the other side of the prolongation of the face, striking its exterior direct but under a small angle, thus taking in flank the embrasures of the face and more readily destroying them without being exposed to direct fire from the face. The locality sometimes renders it obligatory to make the artil- lery^ attack a direct one, as at D. This is the least advantageous of all. The dotted line of the figure represents more nearly actual lines of field-works. The principles, however, remain the same. In determining positions for batteries, those nearest the enemy are not necessarilj"^ the best ; in fact, the greater the range the more searching will be the fire. The projectiles will not have the same power of penetration and destruction at long as at (403) 404 ATTACK AND DEFENSE OF POSITIONS. short range ; nevertheless, for ordinary warfare they possess snf— ficient of these qualities to perform the work required of artillery against field hxtrenchments. 650. The following table, showing the drop of projectiles at various ranges, indicates the importance of this factor in actual warfare. Fig. 1, Plate 70, illustrates this graphically, and, fur- thermore, furnishes useful suggestions as to defilading works by means of traverses and epaulments. See also table and remarks^ \n par. 619. Drop of projectiles. Range. Yards. 200 400 600 700 800 1000 1100 1200 1400 1500 1600 1700 1900 2000 2500 3000 3500 4000 4600 RiFLK-MUSKET. Drop. Seconds. 85 50 30 25 20 14 0.5 1. 1.75 2.*5' 3.75 Veloc- ity. Feet. 1120 915 800 7*66 625 558 506 412 8-Inch Rifle. Drop. 57.3 28*6 r9*.*6 14.3 11.4 8.1 6.3 5.1 4.1 100-Pdb. Parkott. Drop. 57.3 28'.'6 19.0 14**3 11.4 8.1 7.1 5.8 O D 3 Son to S © ;h rj O S fl f^ Eh a 13 .-3 2; O d When the distance to the object can be determined and the range is such as to require considerable elevation, it is by no means necessary that the object should be seen from the gun, provided i*ange-points can be accurately established, as in mortar firing. This is illustrated by Fig. 2, Plate 70. In many cases it will be a great advantage to locate guns in this manner, for the reason that the enemy will probably not be able to ascertain their position witli sufiicient accuracy to do them much damage. Should the distance behind which cover can be obtained be quite short, as represented in Fig. 3, Plate 70, the charges for guns may be reduced so as to allow the necessary elevation to be given to carry the projectiles over the cover, and at the same time drop them into the enemy's works. A few trial shots will enable the artillerist to accomplish this with certainty. Siege howitzers are used advantageously in this way. ATTACK AND DEFENSE OF POSITIONS. 405 651. In nearly all cases the attack has the advantage over the defense, in the amount of fire that can be brought to bear xipon any particular point. When a position can be completely -surroundecl, as is frequently the case in sieges, there is no limit to the amount of fire that may be brought to bear upon it, ex- Xiept the limit of ability to obtain the requisite quantity of pieces and ammnnirion. It is therefore possible to throw into tlie place such a hail of projectiles as to make it impossible for the defend- ers to show any resistance. In most cases, however, the place can be but partly surrounded ; nevertheless, the great range and ability for concentration possessed by artillery enable it to ac- complish like results. It is very certain that, under such cir- cnmstances, the endurance of a place is only a matter of time. The belief at present prevails, to a considerable extent, that it is almost impossible to carry by assault intrenched positions, if resolutely defended by troops armed with the breech -loading ■musket. Such being the case, the only alternative for dislodg- ing an enemy so situated, and who cannot be starved out, is by the use of artillery, — a fact that calls for the more liberal use of this arm and the most skillful handling of it. 65S. With suflicient artillery an enemy can be driven, as before stated, from any position he may occupy. But as there is a practical limit to the amount that can be supplied — and this may fall below what is necessary for actually dislodging him — all that can be expected of it is, to so extinguish the fire of the enemy as to enable the infantry to gain possession of the works, as formerly, by assault. In preparing to make such an attack, the first thing to be done, after determining the particular part of the work to be assaulted, is to establish the batteries and ascertain by experimental firing how to use them so as to make every shot tell. Every available piece should be put in, and other parts of the line stripped tem- porarily in order to make the assault certain of success. 653. The infantry, in the meanwhile, has intrenched itself on a line as near as practicable to the enemy, and organizes into three lines for the assault. The artillery opens and keeps up an incessant fire. When it is seen that the enemy have been driven to cover, the first line of infantry advances as a thick line -of skirmishers composed of detachments, each detachment being under control of its chief. If the enemy show themselves, this line opens fire and assists the artillery in suppressing them. The men of each detachment keep together, and the detachments, taking advantage of everj'' accident of ground for cover, rush forward from point to point as opportunity offers. This line is constantly fed and strengthened from the next line in rear, -each detachment sent forward gaining ground until the reverse 406 ATTACK AND DEFENSE OF POSITIONS. side of the enemy-s work is gained ; seeing which, the second or main line rushes forward, and the whole clamber over the works and drive out or capture the enemy. The second or main line is formed in company columns, and follows the first, or line of skirmishers, at a distance of about 500 yards — less when possible. The third, or reserve, is about 300 yards in rear of the second, and Is massed by battalions ready to be moved where required. The lines of infantry are about of equal strength; i. c, each one-third of the assaulting force. 654. The artillery at first uses shell, but as the infantry ad- vances, and it becomes necessary to fire over it, only solid pro- jectiles will be used ; and fire with these must be discontinued when the infantry has approached so as to be in danger from it. This is the most critical moment; but if positions for the bat- teries have been selected with skill, those on the flanks will be able to keep up a cross-fire until the final rush is made. The artillery commander must have this matter so in hand as to be able to commence or stop the fire from any battery at any mo- ment. To accomplish this each battery should be in telegraphic communication with him, and he must have a position where he will have a clear view and knowledge of what is going on at the point of assault. As a general rule, it is well for the batteries, instead of sus- pending their fire, to increase the elevation so as to throw their projectiles beyond. This, besides checking and disorganizing reinforcements coming up to the enemy from the rear, will have a salutar^y moral effect upon him at the point of assault. When, as is generally the case, the front of the work is pro- tected by abattis or other obstructions, pioneers must accom- pany the first line to clearways for the company columns of the second line to pass through. The artillery commander will select a proper number of de- tachments, placed under suitable oflScers, to advance with the second line for the purpose of turning upon the enemy such pieces as may be captured with the works. These detachments will carry with them sponges, rammers, primers, and lanyards. Ammunition will generally be found with the captured pieces. The most precise instructions are usually given to division, brigade, and battalion commanders as to what they are to do after getting possession of the work; otherwise the troops take no precautions against a counter-attack. As soon as practicable, the artillery commander moves batteries forward to establish a new line on the works just captured. It is his duty to take pos- session of all captured artiller}' material. An accurate and com- plete inventory must be made of it, together with an account of the part it had in the defense of the place ; this, in order that SIEGES. 407 there may be no uncertainty as to the honors dne to various parts of the capturing force. Assaults should be made early in the day, so that the assault- ing force will have time by daylight to push and make perma- nent its success. If night intervenes, the assailed may take advantage of it to reorganize a new line as strong as the first. A dense fog is most favorable for an assault, as the assaulting force is then able to see plainly that which is immediately around it, without itself being seen by the assailed. For the same reason, if made at night, bright moonlight is favorable. It may here be mentioned that artillery of batteries in posi- tion possesses an advantage over all other arms, in being able to be used as well by night as by day ; and this is one powerful element in its favor when protracted operations are carried on against an enemy established in works. If the strength of the works is such that they cannot be car- ried in the manner just described, then recourse must be had to regular approaches and siege operations. Sieges. 655. A place is said to be closely besieged when it is so in- vested as to prevent those within receiving succor from without. When such an investment can be effected and maintained, time alone will effect, by starvation, the work of reduction. When the operations against the place are confined to a simple inter- ruption of communications, it is termed a blockade. In most cases, however, a place can be but partly invested. The besieging operations then consist in regular approaches against particular parts of line of the besieged, reducing them in succession so as to force him to abandon the place which he has attempted to defend. No siege can be successfully prosecuted unless the resources of the attacking army, especially in artillery, are superior to those of the besieged. 656. When a siege is to be carried on by regular approaches, the work so attacked should be enveloped as far as possible by a line of batteries containing the heaviest pieces within the re- sources of the besieging party. These batteries are connected by a rifle trench for the accommodation of the infantry supports, and to form a covered communication from one end of the line to another. It also serves as a secure and convenient place for the accumulation of material for the prosecution of further opera- tions. The line thus formed is called the first parallel ; its dis- tance from the besieged work depends, in a great measure, on the character of the ground ; if this is undulating and broken, so as 408 SIEGES. to form natural approaches to the batteries, the distance may be much less than when the country is level and open to the tire and view of the besieged. As a rule, it should be just without the zone of very destructive fire from small-arms. This, with the present rifle-musket, is about 1500 yards, a distance permitting of the effective use of the artillery mounted along the line. The batteries containing guns, especially those of heavy calibre, should be located on the flanks of the line, leaving the interme- diate batteries for mortars; this, for the reason that guns so sit- uated will not be masked and have their fire checked by subse- quent operations. Mortars can at all times maintain their fire over the heads of troops occupying advanced positions. If the enemy occupy intrenched positions in front of the main work to be attacked, fire must be concentrated first upon one and then another of these positions until he is successively driven from them into his main work. Every piece of artillery capable of throwing a projectile into the works should be brought into requisition, and a superiority gained as soon as possible over the artillery of the besieged. 657. In the meanwhile preparations have been made, b5'"the accumulation of material, for the establishment of a second par- allel, several hundred yards in advance of the first. This should be done under cover of night by a line of infantry throwing up a rifie trench. This trench is enlarged until it forms, like the first, a covered way secure from the view and fire of the be- sieged. Communication with the first parallel is secured by means of zigzag trenches, technically called hoyaux. {Fig. 1, Plate 71.) The branches of these boyaux are so laid out that the enemy will not have an enfilading fire along them. Batteries are constructed along the second parallel ; the boyaux are en- larged to accommodate artillery carriages; the batteries are then armed. Gun-shields, mantlets, and all similar devices must be employed for the protection of the guns and cannoneers of these batteries. The distance of this line will admit of the use of the smaller class of mortars, and an abundance of them should be put in it. As a rule, it is not advisable to place in this line pieces of a heavier calibre than siege guns ; this, for the reason that heavier calibres are more difficult to serve, and, besides, the range from the first parallel is quite within the limits of eftect- ive fire from heavy calibres. An unremitting fire is kept up upon the besieged place. Dur- ing the day the guns will be directed so as to sweep along the faces of the works, disabling the guns of the enera}^ and demol- ishing his traverses, magazines, and bomb-proofs. During the night an incessant shower of mortar shells must be kept falling, to prevent repairs and to keep the garrison constantly harassed. SIEGES. 409 658. Usino^ tlie second parallel as a secondary base, the boy- anx are pushed forward towards the salients of the work; when, advanced to within about half the distance from the second par- allel to the work, a third parallel is constructed by running trenches to the right and left of the heads of the boyaux. The third parallel is for the accommodation of strong guards of in- fantry supporting the w^orking parties, who, under this protec- tion, contrive to push forward the boj'^aux. They also use their lire to suppress musketry fire from the vv^orks and to prevent the enemj^ from serving his guns. An abundance of small mor- tars should be placed in the third parallel and vigorously served. As the boyaii-x are continued, it may be found advisable to rD OF d 1^ > o o u tx o o 1 u o o •d u o o g a o -d o 3 o c Remarks. No. and calibre of piece. Pkojectilk. Percuss'n shell . Fuse shell 10 6 4 8 5 4 1 1 1 7 6 2 1 Where located. Solid shot Canister Case-shot ~ 4 3 1 ... 2 ... 2 ... DEFILES. 417 The command of the enth-e artillery is vested in an officer of that arm of service, who, besides other necessary qualifications, should have rank commensurate with the importance of his position. The line of works is divided into sections, each of a size capa- ble of close supervision by the officer assigned to the command of it. Defiles. 66 Y. A defile, in a military sense, is any narrow place the passage of which can be made by troops only when undeployed. Mountain passes, river crossings, narrow isthmuses, and roads through close forests represent the usual forms of defiles. They necessarily imply obstacles in the way to the free movement of armies, and are therefore important features in a theatre of war, and consequently points demanding special attention byway of defensive arrangements. For these no precise rules can be laid down ; nevertheless some general principles may be stated. The chief advantage offered by a defile i$, that witli but com- paratively slight intrenchments a small force is able to hold a position against a much greater; this, for the reason that, owing to the essential nature of a defile, the attacking force must oper- ate in a constrained position, not admitting of much develop- ment of fire. The main object, therefore, is to secure such a column of fire over the defile as to make it impossible for the enemy to stem it ; this is best accomplished by selecting such points as will give an enfilade fii'e. They should be selected with a view to mutual support, and intrenched in such manner as to be secure against capture by coup de main. The enemy must be compelled to make his attacks with divided forces and inferior numbers. This is best accomplished by occupying sev- eral positions within flanking distance of each other. He will, probably, not be able to attack all simultaneously, and it will be a costly operation for him to attack them in detail. The positions should be so chosen as to allow them to con- centrate their artillery fire upon any point where it might be advantageous for the enem}^ to establish batteries, and the artil- lery of the defense should be of such power as to preclude all possibility of his doing so. All hollow approaches, such as would be formed by ravines in a mountain pass, must be search- ed by the fire of artillery. This, as a rule, will require pieces to be placed in open batteries exterior to the inclosed works. Such batteries must be well supported by infantry sheltered in rifle trenches. The whole system should be so connected as to leave 27 418 DEFILES. 110 part isolated or without the support of other parts, and the defense of each point must be stubborn in the extreme to pre- vent the enemy from gaining possession of advantageous posi- tions. All parts of the line or group of works must be in communi- cation by telegraph, telephone, or signaling, or by all three. This is a matter of the greatest moment in securing not only the physical, but also the moral support of the parts. In every case artillery should form a chief feature in the means of defense ; the kind of pieces for the different parts of the system will depend upon the character of the ground and of the nature of the attacks that may be expected. As a rule, all approaches must be covered by fire; wherever horizontal fire cannot be made to roach, mortars must be used. However much the pieces may be scattered, they must be capable of con- centrating their fire upon any position the enemy may assume. As defensive works in defiles are required to be self-sustaining, frequently for long periods, the supply of ammunition must be ample for all probable wants. If a defile is to be held for the purposes of an army either advancing or retiring in front of an enemy, the head of it to- wards the enemy must be secured by a line similar to a Ute-de- pont; this, for the purpose, if advancing, of giving room for the army to deploy after passing the defile, and to prevent the en- emy from striking it while defenseless in column; if retreating, the same disposition is necessary to hold the pursuing army in check while the troops are defiling to the rear. In both cases, as the object is to keep the enemy from closing in for a pitched battle, artillery must be freely used. In the attack upon a defile, intrenched, armed, and defended as it should be, artillery will be the most important weapon ; this, for tlie reason that, from the very nature of defiles, other arms can act but feebly, while artillery possesses the power of reaching its object beyond intermediate obstacles. As much artillery should be brought to act as possible, and, although it may be widely dispersed, its fire must be concentrated upon some particular work in the system of defenses. The work must be attacked with such vigor and persistency as to insure its destruction and easy capture. Other works, successively, are attacked in the same manner. The operations upon both sides thus partake of the nature ol a siege, and are governed by the same principles. RIVERS. 419 KlVERS. 668. Rivers traversino- the theatre of war occupied by hostile •armies have a marked influence on the operations of each. Wlienever they are to be crossed in the presence of an enemy, either in advancing or retiring, the use of artillery and of field- works becomes of great importance ; this, for the reason that the operation of crossing necessarily consumes considerable time, during wliich the army is divided — astraddle, as it were, the stream — and requites the aid of that arm which, from a fixed position, possesses the power of covering at long range the movements of other troops. The place of crossing, whether bridge, ferry, or ford, is sim- ply a defile through which the army has to pass, and which must be completely covered from the fire of the enemy, who must not be permitted to establish batteries within range of the crossing. This is best effected by covering every point accessible to him with the fire of artillerj'". A river in front of an army operating on the defensive, stands to it, somewhat, as a wet ditch does to a fortification, and should be so guarded as to make the crossing of it a difficult, if not a hazardous, operation to an advancing enemy. Points at which the communications of a country converge are those most ad- vantageous for an enemy to select for crossing. These should be secured by strong inclosed works, armed with artillery of such power as to cause liim to make a long detour and to adopt a less advantageous point. If the stream is navigable, such works form a place of refuge for the craft that ply on it, and which, falling into the hands of the enemy, would furnish him with means of crossing and Assist him in carrying on his operations. The size of the work will, to a great degree, depend upon the force that can be detached from the main body for garrisoning it ; but, generally, a well-constructed work containing a thousand men, adequately supplied with artillery, will prove a formidable obstacle to the crossing army. Points thus established should not be so numerous as to cripple the efficiency of the defending army b}^ dispersion. They should be rather in the nature of bases for temporary points of observation along the river, secure against capture by coup de main, and threatening to the flanks and rear of the crossing army. Tete-de-pont. A bridge is protected by a tete-de-pont, the nature and extent of which will depend upon the character of the attacks to be expected. Against mere raiding parties, a redan or lunette — as represented in Fig, 1, Plate 72 — is sufficient. 420 RIVERS. Tu-0 or three pieces of artilleiy may be put in it, but it is prefer- able to locate batteries, as at B and C, on the opposite side of the river, to flank the redan and cross their fire in front of it. Against a large force well supplied with artillery, a line of works (a 6) must be thrown up and well armed with artillery, for tlie purpose of keeping him beyond artillery range from the bridge. Batteries of heavy pieces are placed, as at c d, to flank the line. Tlie operation of crossing a river by an army in presence of a vigilant enemy, is one of great delicacy, as it necessarily con- sumes considerable time, during which it is more or less divided and subject to every disadvantage. Judicious use of artillery is of tlie first importance. The first thing to be done is to gain a footing on the opposite side. This is usually accom- plished by stratagem or by surprise. Before a large opposing force can arrive, batteries must be established on the side from which the crossing is made to cover with their fire a large area of ground opposite. Every available piece must be put in, and the enemy kept back until bridges can be laid and a strong line of infantrj'' passed over and intrenched. Siege guns, owing *o their great range and power, are the best adapted for this service. The batteries should be extended up and down the stream for three or more miles on each side of the crossing-place ; this, for the purpose of enfilading the flanks of the enemy and preventing him from bringing his artillery to bear upon the cross- ing. The place for crossing should be selected, as far as practi- cable, with a view to advantageous positions for batteries. The convex side of a curve {Fig. 2, Plate 72) with hills dominating the opposite side gives every advantage. This secures a cross- fire upon the opposite peninsula, under cover of which the in- fantry line and light field batteries can be thrown forward to a distance of two or three thousand yards and established in an intrenched line as represented in the figure. If the enemy has gun-boats on the river, especially if they are iron-clads, provision against them must be made by laying across the channel lines of submarine mines, with heavy batteries es- tablished for their protection. These batteries must be strongly intrenched. The operation of crossing a river by an army pressed in rear b}'^ another, is the reverse of that just described. When practicable, the concave side of a bend is selected, across which a line of temporary intrenchments is constructed ; bat- teries are established on the opposite side, and the army with- drawn under protection of their fire. The batteries should cover themselves with gun-pits, and give special attention to such DEMOLITION. 421 :artillery as the eneinj^ may bring forward for the purpose of reaching the place of crossing. * Demolition. 669. Buildings. In military operations it sometimes becomes necessary to destroy buildings, bridges, &c. Wooden structures are readily and effectually destroyed by burning. Ordinary dwelling-houses of stone or brick may be blown down by placing against the walls charges of from 25 to 50 pounds of powder, each contained in a bag, box, or any convenient vessel, and exploded by means of an electric primer, a slow-burning time-fuse, or a piece of slow match. The effect of the explosion is to blow away a portion of the foot of the wall, that above settling down without, as a rule, toppling over. An inside angle or corner of the building is the most advantageous place for the charge, for the reason that, being confined on two sides, the explos^ive force acts more powerfully than when, against a plain surface, and also because the angle or corner of the building, being a point of greatest support, when blown away leaves the remaining parts greatly weakened. Against strong and massive walls, such as are generally found in large public edifices, charges of powder, unless very heavy, have but little effect when simply exploded against the wall without tamping. Inside angles should, if possible, be taken, or when the building has buttresses, the angles formed by them are advantageous for confining the explosive force and causing it to take effect on the wall. The powder is placed in a box or keg and covered with earth and stones. When placed five or six feet above the foot of the wall the effect is greatly increased. In all cases where demolition is to be produced, dynamite may be used instead of gunpowder. Its destructive effect is about thirty times that of powder, weight for weight. Bridges. To destroy the arches of a masonry bridge, exca- vate a hole down to the crown or haunch of the arch, place in it a charge of one or two hundred pounds of powder, according to the thickness of the arch, tamp it well with earth and stones, and explode it. The amount of powder is determined from the formula X=5 A2 X B : in which X is the charge in pounds, A the line of least resistance through the arch, and B the breadth of the bridge, both in feet. When the width of the arch is over 25 feet, two charges should 3)e placed, to prevent the chance of blowing a hole through the 422 DEMOLITION. middle without bringing down ,the sides. These should be exploded simultaneously, if possible. When the side walls are lightly built, it is better to pull enough of the stone away to allow a tunnel being run on top of the arch to the middle of the roadway. This does not interfere with the use of the bridge during the operation, and if it is not de- sired to destroy the bridge immediatelj'", the charge may be kept in its place ready for use at any moment. In this case the charge should be in a tight box or barrel, well pitched to protect ife against moisture. The charge may be exploded by means of an electric primer, the ordinary fuse used in blasting, or with a powder hose. This latter is made of canvas or any stuff that will hold fine-grained powder, and is inclosed in a trough to protect it from the moist- ure of the earth. The ordinary blasting fuse is known in this country under the name of tlie safety fuse and Toy's fuse; in England, as Bickford's fuse. It consists essentially of a column of fine-grained gunpow^der inclosed in flax, hemp, or cotton, and made up with different coverings, according to the use to which it is applied. When intended for immediate use on light work in dry sand, it is unprotected by additional coverings; when intended for use in wet ground or under water, it is covered with varnished tape or gutta-percha. These fuses are somewhat uncertain in their rate of burnings but average about one yard in a minute. The ordinary varieties must be kept in a cool, dry place, and preserved from contact with oil. Wooden bridges are easily burnt ; but if great secrecy is neces- sary, a hole may be bored with an auger in a main-brace and a charge of powder or dynamite exploded therein, blowing it to pieces. Charges should be placed in several of the braces and exploded as near simultaneously as possible. During the war of the rebellion a small torpedo was devised for this purpose. It consisted of a tin cylinder 1.75 inch in di- ameter and about 7 inches long. Both ends of tiie cylinder were open, and through it passed a bolt of 0.75-inch iron, with a stout head at one end and a nut at the other, each having a diameter of 2 inches. A washer of the same size as the head was placed under the nut; through a hole in the washer passed a strand of slow match to communicate fire to the powder with which the cylinder w^as filled. A coat of varnish protected the powder Irom moisture. To use it, a hole 2 inches in diameter was bored? DEMOLITION. 423 in the timber; into this the torpedo was driven, head down- wards, and the fuse ignited. • The most effectual way of destroying an iron bridge is to at- tacli the abutments by mining down so as to get behind the masonry a large charge of powder or dynamite, which being exploded, destroys the supports of the superstructure. When time and means permit, remove as many bolts as possible, so as to weaken the parts, after which build a strong fire and heat the main-braces to tnake the bridge sag and warp out of shape, or to come down entirely. Canals. These may be temporarily disabled by cutting em- bankments. The most effectual way, however, is to blow up a lock, which maj^ be done by digging down behind a facing wall and placing against it a charge of two or three hundred pounds of powder or a few pounds of dynamite, tamping well and ex- ploding it. A lock destroyed in this manner requires a long time to repair. The arches of an aqueduct may be broken by drilling holes and blasting. An arm)-^ depending upon a railroad for its supplies should be provided with an organized construction corps, fully equipped with every means for making speedy repairs. Damages done to railroads are easily repaired, in comparison with those done to canals. prt ptttft. SUBMARINE MINES. CTO* The term torpedo^ when used in a niilitary sense, desig- nates those contrivances for producing explosions calculated to act destructively against an enemy coming into their immediate vicinity. Tliej^ are chiefly used for obstructing rivers and entrances to harbors, and are either stationary or capable of movement. When stationary they are called submarine mines^ leaving the term torpedo for all ofl:ensive and movable combinations of this nature. The use and application of the latter fall more partic- ularly to the province of the Navy, the former to the Army, and, being employed as auxiliary to shore batteries, constitute a branch of service naturally belonging to or intimately connected with the artillery arm. Submarine mines are applicable to almost any situation liable to be attacked by ships, but in every instance they should be so arranged as to be covered by the guns of forts or detached bat- teries, so that, while acting as outworks of these latter, they will be protected from destruction by boats from a hostile fleet. The comparatively small cost of this species of defense allows of its extensive use as an agent to deter an enemy from approach- ing a fortified position, and to cause him to begin the tedious and dangerous operation of clearing the channel, or to land and at- tempt to capture the place without the aid of his ships. This in most cases would enable the defenders to hold out until the arri- val of a relieving force. The materials required for most submarine mines are articles of commerce easily procurable, or capable of being kept on hand without damage or loss, and a system of defense by such means a radiating form from a central point of observation, at a dis- tance of about 20 feet, and with pieces of twine passing from the centre over the picl^ets in tlie direction of the mines to indicate the bearings more accurately, very good practice has been obtained. The observer, with liis e3^e at the central picket and his hand on the contact keys, puts the corresponding one down as the object passes the bearings of each. A man soon learns bj'' practice the distance he may allow on one side or other of the bearing line, and with ordinary care and nerve is soon able to make contact at the right moment. ^-'In using the keys, it is necessar}'- to press them firmly down and hold them firmly, in order to insure good contact at tlie proper moment. '*'To work efficiently, it does not seem desirable that more than six keys should be intrusted to the management of anyone man. ^'The sj^stem of pickets above described for giving the bear- ings might probably be used efifectually up to half a mile, but at greater distances a more accurate means of obtaining the inter- sections becomes necessary; the pickets have, moreover, the disadvantage of being easily disturbed and difficult to replace in an accurate position if once moved. In order to obviate as far as possible these defects, an instrument has been devised- having a telescope, with cross-wires, mounted in connection with a series of contact points and a movable key, as shown in Fig. 3^ Plate 75. It consists of a iieavy cast-iron stand (a), on which is placed an iron upright (6) arranged to carry the telescope (c), allowing it a horizontal motion around the upright; it has also a vertical motion. Concentric with the upright is a circular arc (f?), described with a radius of about 18 inches. On this arc are arranged the contact points for the cables running to the mines- or to the other station. Attached to the upright, below the tel- escope, is a horizontal arm (e), which moves around with the telescope. To this arm is attached a contact key (/*), adjusted' to touch the contact points on the arc. The arc is graduated into divisions, by means of which the position of the contact points may be registered, so that in the event of their being accidentally displaced they may again be fixed in true relative position with facility." To place the instrument in position, a point from which the lines of mines are clearly distinguishable should be chosen. ThiS' point should be as far as possible from heavy guns and have a^ solid foundation. The iron stand of the instrument having beert leveled by means of leveling screws, the telescope is directed on- some fixed and well-defined object, and the number of the: 454 MECHANICAL CIRCUIT-CLOSERS. -division under the spring of tlie lever registered. The telescope is then directed on each buoy marking the mines of each line, in succession, and one of the contact ai-rangements brought into proper position for each and l^eyed firmly up, and the num- ber of the mine and the number of the division on the gradua- tion are registered. This having been done at both stations, the buoys marking the positions of the mines are removed. The points w^here the leveling screws of the iron stand rest should be carefully marked, so that the whole may be placed in the same position if accidentally disturbed. The observations are made through the telescopes, and when a vessel comes in range with any mine, as indicated by the regis- tered degree, the corresponding key is put down, the operation being in every other respect as before described. 691. Mechanical circuit- closers. These are arrangements by which submarine mines are fired electrically by the vessel herself closing the circuit. They are of two classes, one being that in which the charge .and the circuit-closer are in the same case, and the other is where the circuit-closer is in a separate case, but connected with the charge of the mine by an electrical cable. In botli ways, the conducting cable is electrically charged from the battery on shore up to the circuit-closer; when this latter is closed by con- tact with a hostile vessel, the current passes through the fuse in the charge and the mine is exploded. A great rmmber of differ- ent forms of both classes have been invented, all of which are more or less complicated and require special description and study to understand. To render mines thus provided with circuit-closers harmless to friendly vessels passing, it would be necessary only to detach the firing battery — an operation usually performed by the operator dimply removing a small plug. In this case the circuit-closer, if strongly made, may be struck time and again without injury. This power to resist heavy blows is essential to the efficiency of any form of circuit-closer, as, when in position in a channel through which there is much traffic, they are always liable to be struck with considerable force by blades of screws, floats of paddles, and other hard and sharp bodies. Another especial considera- tion is, that the appai-atus for closing the circuit shall not be set in action by agitation of the water, but only by impact with a 'floating body. The circuit-closer must furthermore have suffi- cient size to give the required amount of inertia. When the circuit-closer and charge are combined in the same case, this is assured ; but when they are separate, it is effected by inclosing the mechanism in buoys made of wood or metal. The greater MECHANICAL CIRCUIT-CLOSERS. 45^ the size and weio^ht of the ch-cuit-closer, the greater will be the chances of the effective worlving of the apparatus. The destructive power of a mine decreases rapidly as the dis- tance from it increases. The circuit-closer should not, there- fore, be beyond the effective range of the mine. Forty to fifty" feet should be the maximum distance for the heaviest charges. 692* The arrangement of a system of submarine mines in lines possesses the disadvantage that if the enemy has once as- certained the position of one mine of a line, whether by explo- sion or by any accidental circumstance, he would know within what limits the others were to be looked for. In order to obvi- ate this disadvantage, it would always be necessary to scatter a. few mines in irregular intervals in front of the advanced line — to set them as skirmishers, retaining the line formation for the^ main defense. These advanced mines might either be simply electro-self-acting, or arranged for ignition on the same principle as those of the main system, as circumstances required. As it is not advisable to expend heavy charges against small boats, these advanced mines should be comparatively small, so as to be used; against the boats of an enemy seeking for the mines and circuit- closers. "The first object of an enemy would be to clear a passage of sufficient width through the system to enable him to pass freely in; and for this purpose he would probably employ drifters^ with or without dragging grapnels, for the purpose of either firing some of the charges by striking the circuit-closers, or grap- pling and destro3ing the electrical cables and other gear, These- drifters may be boats allowed to float in with the tide or wind. In order to stop such a sj^stem of attack, a light boom or strong, fishing-nets would be useful, and should be employed whenever circumstances permit. To stop drifters with dragging grapnels,, it is a good plan to lay three or four heavy chain cables at inter- vals across the channel, in advance of the system of mines. The grapnels would catch in these, and the weight of the chains would be suflScient to bring up the drifters before arriving at the mines. "The night would unquestionably be the safest time for the enemy to carry on operations of this nature, and it would be necessary to employ Ijoats to row guard in order to watch his proceedings. The mode of communication with these boats is a matter of considerable importance, and some means of rapidly transmitting intelligence is absolutely necessary. This can. o£ course, be done by the system of flashing signals, but the lights in such case would be a disadvantage, as they would indicate to the enemy the position of the guard-boat. In order to obviate: 456 TESTING. this, a system has been devised by vvliich a boat rowing guard 'Can be put in electrical telegraphic communication with a fort or guard-ship, by simply paying out an insulated wire attached to a telegraph instrument in the fort or ship, and carrying a second instrument on board the boat. Should the guard-boat be pursued, it would only be necessar}^ to detacli the electric cable from the instrument and throw it overboard, with a buoy and line at- tached to it, and pull awaj'. ""Several systems have been devised for illuminating chan- nels at night by means of the electric light, the Drummond light, magnesium light, <&c., and there is no doubt that, when practicable, such devices should alwa3'^s be used." 693. Testing. In the electrical-room of the fort are kept iihe instruments for testing the electrical cables of the mines, for the puipose of seeing that they are in condition to perform their work efficiently. The most essential instruments are the test- table and galvanometers. With these the cables are, from time to time, examined to ascertain if their insulation is effective, and if they have a sufficient amount of electricity ; if the firing bat- teiy is in a condition to insure certain ignition; if the electrical connections of the circuit-closers are correct; if the electrical resistance of the fuse is such as to indicate certainty of ignition, and other similar information. A separate galvanometer should be used for each mine, and a special battery, distinct from the firing battery, employed in connection with the testing circuits ; thus obviating the necessity of detaching tiie firing battery while testing, — an important mat- ter likely to occur at the critical period when vessels are attempt- ing to break through the lines. Should a leak be discovered in a cable, the extent of it is shown hy the galvanometer ; and if considerable, the defective cable is detached from the battery and the fault repaired. When a mine is tired, it is important that its cable should be disconnected at once from the firing battery, to prevent loss of powei- through the broken end of the conductor. When a separate galvanometer is supplied for each cable of a system of a mines, it furnishes a constant indicator to point out the fact of a circuit-closer being struck by a ship, and in many cases it may be convenient, or even necessary, to perform the operation of tlirowing in the firing battery without the aid of a personal operator. A self-acting apparatus has been devised for doing it. By making the apparatus purely self-acting, all •chances of error consequent upon the inattention or want of dex- terity of fehe man in charge is, of course, eliminated. No mine or circuit-closer can be tampered with by an enemy without the TESTING. 467 fact being instantly Ivnown in the testing-room, and precisely what mine. As it is of importance to be assured of the condition of the charge in the mine, whether dry or wet, an apparatus for this purpose has been devised, and it is of easy application. The use of it obviates tlie necessity of the great labor, time, and trouble that would be required to raise each mine and, by opening it, ascertain in that way the condition of the charge. *' The firing battery should be suited to the nature of the fuses employed, and should possess considerable excess of power in order to overcome accidental defects ; such as increased resist- ance in the communications, or defective insulation in the elec- tric cable in connection with the mine. A battery just suffi- ciently powerful to fire a fuse on shore, with the electric cable, &c., in circuit, but not submerged, would not be unlikely to fail after the cable has been submerged in sea-water. In such a case it is recommended that the battery power determined by such an experiment on shore be doubled for actual work. For all practical purposes this test can be made by firing a fuse of known quality through a resistance equivalent to that of the cable. Double the number of cells necessary to effect this would be re- quired for the submerged cables, &c. '* When a system of mines is to be laid, each component part should be tested before being placed in position and, afterwards, as the parts are successively combined in the form in which they are to be used before submersion, and the whole should again be tested immediately after submersion. ''As a preliminaiy to all electrical testing, it is necessary to ascertain if the instruments, battei-ies, &c., used in making the tests are themselves in good working order; otherwise defects which exist in the testing instruments may produce results which might be mistaken for defects in the apparatus under trial." The cases are tested at the time of manufacture to ascertain if they are thoroughly water-tight and capable of bearing the ex- ternal pressure to the extent required, according to the depth to which the)" are to be submerged. A very practical test for this is to close the case with its proper mouth-piece as for service, and then submerge it to a depth somewhat exceeding that at which it is eventually to be used. After remaining thus sub- merged for about forty-eight hours, it is lifted, opened, and care- fully examined to see that it has remained perfectly dry inside. A careful record should be kept of the results of all electrical tests applied, as by preserving tlie electrical history of any com- bination a defect in its electrical condition maybe readily dis- covered, and the nature, position, and extent of such defect 29 a 458 SURFACE CURRENT OF HARBORS. indicated with a considerable de^^ree of accuracy, without the necessity of raising the mine out of water, or in any way dis- turbing the arrangements employed. The foregoing will suggest to officers charged with harbor defenses the capabilities of submarine mines as an auxiliary to land defenses. It also furnishes an idea of the kind and quan- tity of material required for establishing a system of mines, and indicates the method of applying and using it. Dexterity in the use of testing instruments — in fact, all the electrical manipulations connected with submarine mines — is to be acquired only by practice, with the aid of treatises on such subjects. Experience has proved that, with persons of good intelligence, the necessary qualifications may be acquired in a period of six months. 694. The following table gives the maximum surface current for some of the principal harbors upon the Atlantic sea-board. It will be useful in determining the kind of moorings necessary for securino; submarine mines in these channels : Locality. Portsmouth, N. H., in the channel off Fort Constitution. Boston Harbor, Mass. : 1. Boston Light-house bearing N., distant }^ mile ; depth of water 33 feet 2. Broad Sound Channel, Long Island Light- house bearing S. by W., distant K mile ; depth of water 58 feet Entrance to Narragansett Bay, main channel New York Harbor, Narrows ; Fort Lafayette bearing N. E., distant H mile; depth of water 90 feet Delaware Bay, in the channel abreast of Brandywine Shoal. (No observations were made near Fort Delaware) Hampton Roads, Ya., Old Point Comfort Light-house bearing N. M E., distant H mile; depth of water 78 feet Beaufort, N. C, Fort Macon wharf bearing S., distant % mile; depth of water 26 feet Cape Fear River, west entrance, Fort Caswell bearing N. W., distant Jed bomb-proof covering overhead. This arrangement is termed a defensive casemate. This method of defense is only efficacious against a sea attack; for on the land side, where the enemy can approach regularly, casemates would be rapidly destroyed by his batteries, and the loss of life would be far greater in them than in an open defense, owing to the fragments of stone which each shot striking an embrasure would cause. The arch of the casemate is supported by piers extending back from the scarp-wall. These piers are usually about six and a half feet thick, and, a few feet back from the scarp-wall, are pierced by arched passage-waj^s, which, besides securing free communication from one casemate to another, gives the gini- carriage a wider traverse by allowing the rear end to run under this opening. The arches of the casemates are of brick, and have a thickness of three feet exclusive of the roof-shaped capping, which is gen- erally of rubble and b^ton, and covered on top by the earth of the rampart and parapet. At least six feet of earth is necessary to give full security against shells. Arched recesses are made in the scarp-wall at the embrasure to permit the gun being well run out to prevent the smoke from entering the casemate. Tiie embrasure is in the centre of the recess, the sole being at the proper height for the easj^ service of the piece. In some casemates, flues for ventilation and carrying ofl" rapidly the smoke of discharge run from the top of the carriage recess through the masonry of the scarp-wall, and have their outlet in the top of the wall outside. In others, the flues run from the casemate arch to the top of the scarp-wall. Beneath the embrasure, a recess, termed the tojigue-hole^ is made to receive the tongue of the chassis. The tongue is con- flned in its place, and the chassis traversed around a pintle, which is received into t\\Q. pintle-hole made at the centre point of the throat of the embrasure, and extending into the masonrj' below the tongue-hole. When the casemate serves also as quar- MAGAZINES. 458g ters for the garrison, the rear, towards the parade, is closed by a rausonry wall, which forms tlie front of the quarters. A brick partition wall separates the quarters from the gun-room. Built up with this wall are fire-places, with flues extending to the parapet above. The front or parade end of the quarters is suitably finished, with doors and windows. In contracted situations, wiiere it is desirable to secure greater fire in a fixed direction than can be had from a single tier of casemates, one or more tiers are added, the parapet being re- tained as before. The arclies of the top tier are alone bomb- proof; those of the lower tiers being of sufficient strength to re- ceive the armament and admit of the service of the guns with safety. Mortars being placed behind the ramparts or traverses to secure them against horizontal fire, are protected from vertical fire by arches covered with earth, as in the preceding case. The arch rises towards the front to give room for the sliell in its flight. The front end of the casemate is walled up to a height of about six feet. This permits the mortar to be firied over the wall, and the interior of the casemate is protected to a great degree from falling shells and splinters. Casemates are also used simply as bomb-proof shelters for the troops and material. These vn'Aj be constructed in the ramparts of land fronts, where guns are used onlj'- in barbette. Upon land fronts, where it is important to have the masonry covered by earth from the fire of stationary batteries, embrasures are made in the parapet after the manner prescribed in par. 634. The arch of the casemate is united to the interior slope-wall, as, in the preceding case, it was to the scarp-wall. Its covering of earth extends down in front, forming the merlons of the parapet, thns covering all the masonry except that of tfie embrasure. The front portion of the arch of the casemate is conoidal, and descends down to the top of the embrasure. Magazines (see pars. 569, 637) for permanent works are con- structed usutdly in connection with the enceinte, being placed in the most secure part of tiie work. They are built with strong, full centre bomb-proof brick arches, supported on heavy masonry piers, which form the outward walls. The arches are covered with not less than eight feet of earth. The interior of the magazine, the floors, and the doors and ^vindows are built with a view to security from fire, and to pre- serve the powder from dampness by a good system of drainage ^around the foundations, and of ventilation by means of air-holes \ 458h detached works. made throiio^h the piers and panels of copper pierced with small holes placed in the doors. No iron or steel is allowed in any part of the structure, bronze being used where it is necessary to employ metal. The exterior openings for air-holes are covered with copper mesh-work to prevent combustible material or rats or mice pene- trating to the interior of the magazine. Heavy guns are usually placed in pairs, with a traverse be- tween each set of pairs. In this traverse is built the service magazine for the adjacent pieces. Advanced works are those placed bej'ond the outworks, and are so under the fire of either the main work or the outworks a& to have the ground in advance of them swept by this fire ; their ditches flanked hj it, and their interior so exposed to it. that if the work were seized by the enemy he could be driven from it by tliis fire. Detached works are those which, although having an important bearing on the defense of the main work, are so far from it as to have to depend solely on their own strength in case of assault. Explanations of Plate 77. Plan of a regularly fortified front : A A . . A is the enceinte, or body of the place. BB, the bastions. CC . . C, the main ditch, or ditch of the enceinte. DD . . D, the bastion and demi-lune covered-ways. E E, the reentering places of arms. FFF, the salient places of arms. G, tiie demi-lune. H, the demi-lune ditch. J, the demi-lune redoubt. LL, the'ditch of the demi-lune redoubt. MM, the redoubts of the reentering places of arms. a a . . a, traverses of the covered-way. o, the tenaille. Fig. A shows a section of the enceinte, main ditch, and cov- ered-way. A is the rampart; of which a 6 is the slope, and he the terre-plein. B is tiie parapet ; of which cdegh is the outline. C is the main ditch. D, the scarp wall. E, the counterscarp wall. F, the embankment of the covered-way; of which mn is the terre-plein, n op the outline of the banquette,, interior slope, and glacis. iart mmntU. SALUTES AND CEREMONIES. This subject is introduced under the following authority : Navy Department, Washijstgton, Nov. 20, 1879. Sib : Referring to your letter of the 30th ultimo, transmitting^ the mantt- script of a "Chapter on Artillery Salutes in G-eneral," by Major Tidball^. of the United States Army, I have the honor to inform you that the officeris of the Navy to whom it was submitted report that it confonns to naval usage and the conventions with foreign powers with respect to the etiquett©' of visits and salutes. The manuscript is herewith returned. Yery respectfully, (Signed) R. W. THOMPSON, Secretary of the Navy. Hon. GrEORGE "W. McOrary, Secretary of "War. , Approved : By order of the Secretary of "War. (Signed) JOHN TWEED ALE, Acting Chief Clerk. War Department, Nov. 26, 1879. 695. A salute with cannon is a certain number of guns fire^" in succession with blank cartridges, in honor of a person, to- celebrate an event, or to show respect to the flag of a country.. Tiie i-apidity with which the pieces are discliarged depends upon their calibre. Field guns sliould have intervals of five seconds between discharges; siege guns, eight; and guns of heavier calibre, ten. The minimum number of pieces with which salutes can be fired is two for field, four for siege, and six for sea-coast guns. Mortars, as a rule, are not used for saluting purposes. 696. Personages entitled to salutes, if passing a mihtary^ post, as also foreign ships-of-war, are saluted with guns of heavy calibre, the most suitable being the 10-inch smooth-bore. When trooi)s are drawn up for the reception of a dignitary,, and it is practicable to have a battery of field guns on the ground, a salute from it should form part of the ceremony;; otherwise guns in position are used. The national salute, and minute-guns upon funeral occasions,, are, when practicable, fired from heavy pieces. ( 459 ) -460 SALUTES AND CEREMONIES. 697. The pieces used for a salute should, if possible, be of the same or equivalent calibre; and when the number on the front of a work admits of it, the entire number required, and two or tliree over, should be loaded and made ready previous to commencing the salute; the detachments are then dispensed with, and a single cannoneer at each piece discharges it at the proper time. When the number of pieces is insufficient for the entire salute, as many as possible should be used, so as to avoid frequent reloadings. 698. The pieces are numbered from right to left, — one, iwo^ 'ihree^ and so on, — and each detachment or the cannoneer, as the case may be, is made to clearly understand the number of the piece. To insure regularity of intervals, the officer in charge ^of the firing should habituate himself to uniformity in giving the commands to fire. At the proper moment the officer in charge commands : Num- ber one^ Fire, and observing the proper interval, Number two^ Fire, and so on to the left piece, when he returns to the first and repeats the same commands until the entire number re- quired for the salute is discharged. In order to preserve regu- larity in the fires, he will not concern himself with the running number, but will have a capable person to keep the count and notify him when the required number of discharges are made. In giving the command Jire^ he looks towards the piece to be fired, and gives it in such a pronounced manner, accompanied 'Tjy a signal with his sword, as to be unmistakable; the can- noneer discharging a piece, when its number is called casts his eyes to the officer, and, observing the signal as well as the com- mand, pulls the lanyard with promptness and decision. The officer will be careful to avoid excitement in himself or to cause it in the men firing the pieces. Should a piece miss fire, he immediately commands the next to fire, and allows the piece that has missed to remain undischarged until its proper turn -again comes. Immediately after each piece is discharged it is reloaded and made ready. The cartridges are withdrawn from the pieces that remain loaded at the conclusion of the salute. 699. Salvos are simultaneous discharges from several can- Son. They correspond to volleys of musketry, and are fired, y way of salute, only over the graves of officers at the time of burial. The order designating a funeral escort prescribes whether the fire shall be three volleys of musketry or three salvos of .-artillerj''. The following are prescribed salutes : NATIONAL AND PERSONAL SALUTES. 461. National Salutes. I'OO. The national salute is one gun for each State in the- Union. The international salute^ or the salute to a national flag, is- 21 guns. Personal Salutes. YOl. To civil and diplomatic authorities. The President of the United States receives a salute, to be given both on his arrival at and final departure from a military post or station provided with artil- lery, of 21 guns.. The Vice-President of the United States 19 guns- Members of the Cabinet, the Chief Justice, the Speaker of the House of Representatives, the Governors with- in their respective States or Territories 17 guns. A committee of Congress officially visiting a military post or station 17 gnns» The Sovereign or Chief Magistrate of a foreign State, to be given both on ai'rival at and final departure from a military post or station provided with artillery 21 guns* Members of the Royal Familj', i. e., the Heir-apparent and Consort of the reigning sovereign of a foreign State 21 guns. The Viceroy, Governor-General, or Governors of prov- inces belonging to foreign States 17 guns. Ambassadors Extraordinary and Plenipotentiary 17 guns- Envoys Extraordinar}' and Ministers Plenipotentiary.. 15 guns. Ministers Resident accredited to the United States 13 guns. Ciiarg^s d' Affaires, or subordinate diplomatic agents left in charge of missions in the United States 11 guns. Consuls-General accredited to the United States 9 g-uns. te' "YO^. To military and naval officers. The General-in-Chief, Field Marshal, or Admiral 17 guns. Lieutenant-General or Vice- Admiral...., 15 guns. Mujor-General or Rear-Admiral 13 guns. Brigadier-General or Commodore 11 ginis, Otficers of volunteers and militia, only when in the service o£ the United States, the salute specified for their rank. Officers of foreign services visiting any military post or station^ provided with artillery, are saluted in accordance with their* rank. 462 NATIONAL AND INTERNATIONAL SALUTES. In addition to the foregoing, occasions of a public nature frequently arise when salutes are both desirable and proper. Orders will govern in such cases. Personal salutes are, however, strictly confined to the foregoing, and are fired but once, unless •otherwise specified herein. f ©3. Salutes are fired only between sunrise and sunset^ and, us a rule, never on Sunday. The national color must always be displayed at the time of firing salutes. TMie national salute is fired at noon on the anniversary of the Independence of the United States at each military post or camp provided with artillery. 7©4. The international salute is the only salute which is re- turned, and this is invariably done as soon as possible. The time intervening must never exceed twenty-four hours. The iailui-e to return such salute is regarded as a discourtesy or lack •of friendship justifying the other party in asking explanation. In the presence of the President of the United States, however, no salute, other than the national salute^ and that specified for liim, is to be fired. 105. It is the custom for saluting vessels-of-war upon anchor- ing in presence of a fort, to hoist at the fore the flag of the coun- try in whose waters they are, and to fire the first salute. A failure to do so is a proper subject for explanation. ]S"otice of an intention to salute the flag is usually given by the vessel direct to the fort; but as giving notice involves delay, vessels frequently salute without it. Vessels mounting less than ten guns do not fire salutes requiring the guns to be reloaded. Surveying vessels, store-ships, or transports do not salute. If there be several forts or batteries in sight, or within six miles of each other, one of them is designated in orders to return international salutes. Either of the others receiving notice from a, saluting vessel of intention to salute the flag, immediately no- tifies the one designated as the saluting fort, and informs the vessel of the fact. If a vessel salutes without giving notice, the fort designated as the saluting fort returns it. United States vessels return salutes to the flag in United States waters, only where there is no fort or battery to do so. United States vessels do not salute United States forts or posts. Salutes to the flag are in no sense to be considered as personal. ^OQ, The President of the United States, the Sovereign or Chief Magistrate of a foreign country traveling in a public ca- pacity, is saluted 'whQw passing m the vicinity of a military post. A vessel-of-war on which the President of the United States is traveling displays the national ensign at the main. In the case OFFICIAL COURTESIES. 463 of foreign sovereigns, vessels display the royal standard of the sovereign in like manner. TOT. Personal salutes, in compliment to foreign diplomatic authorities, are to be fired only for those whose nations pay the same compliments to United States diplomatic ministers in their territories. Personal salutes at the same place and in compliment to the same person, whether civil, diplomatic, military, or naval, are never to be fired oftener than once in twelve months, unless such pei'son shall have been, in the meantime, advanced in rank. Officers on the retired list, whether military or naval, are not to be saluted. This, however, does not apply to funeral cere- monies. An officer, whether civil, military, or naval, holding two or more positions, either of which entitles him to a salute, receives only the salute due to the highest grade. In no event is the same person to be saluted in more than one capacity. When several persons, each of whom is entitled to a salute, ar- rive together at a post, the one highest in rank or position is alone saluted. If thej'^ arrive successively, each is saluted in turn. An officer assigned to duty according to brevet rank receives the salute due to the full rank of the grade to which he has been assigned. As a rule, a personal salute is to be fired when the personage -entitled to it enters the post. When the troops at a military post are to be reviewed by a per- sonage entitled to a salute, it is most appropriate to fire the salute from field guns at the place of review, and at the time, just pre- vious to the review, when the personage arrives on the ground. Official Courtesies. KOS, The interchange of official compliments and visits be- tween foreign military or naval officers, and the authorities of a military post, are international in character. In all cases it is the duty of the commandant of a military post, without regard to his rank, to send a suitable officer to ofi^er civ- ilities and assistance to a vessel-of-war (foreign or otherwise) recently arrived. After such offer it is the duty of the commanding officer of the vessel to send a suitable officer to acknowledge such civilities, and request that a time be specified for his reception by the commanding officer of the post. The commanding officer of a military post, after the usual offer of civilities, is always to receive the first visit without re- gard to rank. The return visit by the commanding officer of 464 OFFICIAL COURTESIES. the military post is made the following day, or as soon thereafter as practicable. "^09. When a military commander officially visits a vessel-of-- war he gives notice of his visit to the vessel previously thereto, or sends a suitable officer (or an orderly) to the gangway to an- nounce his presence, if such notice has not been given. He is then received at the gangway by the commander of the vessel^ and is accompanied there on leaving by the same officer. The officer who is sent with the customary offer of civilities is met at the gangway of a vessel-of-war by the officer-of-the-deck; through the latter he is presented to the commander of the ves- sel, with whom it is his duty to communicate. A vessel-of-war is approached and boarded b}'^ commissioned officers, by the starboard side and gangway, when there are gang- ways on each side. In entering a boat, the junior goes first and other officers according to rank; in leaving a boat, the senior ^oes first. The latter is to acknowledge the salutes which are given at the gang- way of naval vessels. ]N"aval vessels fire personal salutes to officers entitled to them when the boat containing the officer to be saluted has cleared the ship. It is an acknowledgment for his boat to '' lie on her oars" from the first until the last gun of the salute, and for the officer saluted to uncover, then at the conclusion to '""give way.'^ The exchange of official visits between the commanding officers of a post and vessel, opens the door to both official and social courtesies among the other officers. '710. To a boat with the flag of an admiral, vice-admiral, or rear-admiral, or the broad pennant of a commodore, boats with narrow pennants *'lie on their oars" or '■'let fly their sheets," and boats without pennants "toss their oars." In both cases^ officers in them salute. In the case of two boats meeting or passing each other, each with the same insignia of a commanding officer, the junior is the first to salute. Officers of inferior grade to a commanding officer passing him in a boat, *Mie on their oars" or 'Met fly their sheets," and salute. All other officers passing each other in boats are to ex- change salutes, the Junior saluting first. Cockswains steering boats are, whenever commissioned officers are saluted, to stand up and raise their caps, and whenever warrant officers are saluted thej'^ raise their caps only. The officer or cockswain of a loaded boat, or of boats engaged in towing, salute a boat with the flag of an admiral, vice-admiral or rear-admiral, or the broad pennant of a commodore, by standing and raising their caps. OFFICIAL COURTESIES. 465 When boats are rowing in the same direction, an inferior is not to pass a superior in grade unless he i.^ on urgent duty, or authorized by- the superior. When boats are pursuing opposite directions, the rule of the road to prevent fouling is, that both shall "put their helms to port " — i. e., to pass to the right, circumstances permitting. When boats are approaciiing the same landing or vessel, an inferior is always to give way to a superior in rank. Boats about leaving a ship's side or landing are to give way in ample time to others approaching. It is not proper to land over another boat witliout permission, and only when it cannot be avoided is permission to be asl^ed. Boats display their ensigns when they shove off, and keep them flj-ing until their return. '^'11. To distinguisli officers in boats, commanding officers of fleets, squadrons, or divisions carry the distinguishing marks of their rank on the bow of their barges. Flags and pennants dis- tinguishing rank are also worn at the bows of boats. An admiral's flag is a blue flag bearing four v^^hite stars ; that of a vice-admiral bears three stars; a rear-admiral, two stars; a commodore's pennant, one star, and is a swallow-tailed flag. The narrow pennant is worn by commanding officers of lesser rank. In addition, captains in the Navy wear a gilt ball on the end of their boat staffs, and commanders a gilt star. To the ships, boats, and officers of the United States Navy, as well as foreign officers, the foregoing is due; and courtesy be- tween the land and naval services is indispensable to good order and discipline, as well as necessary to the national dignity and honor. Military officers of assimilative rank are entitled to and should carry the above boat insignia. Navy regulations require officers and men never to omit, on any occasion, to extend the same compliments to officers of the Army as are paid by them to officers of the Navy. •yiS. When a civil functionary entitled to a salute arrives at a military post, the commanding officer meets or calls upon him as soon as practicable. The cominanding officer will tender him a review, provided the garrison of tlie place is not less than four batteries of artillery, or their equivalent of other troops. When an officer entitled to a salute visits a post within his own command, the troops are paraded and he receives the honor of a review, unless he directs otherwise. When a salute is to be given an officer junior to another pres- ent at a post, the senior will be notified to that effect by the com- manding officer. Military or naval officers, of whatever rank, arriving at a mll- 30 466 FUNERALS. itary post or station, are expected to call upon the commanding officer. Under no circumstances is the flag of a military post dipped by way of salute or compliment. Funerals. 1'13. When the funeral of an officer entitled, when living, to a salute, takes place at or near a military post, minute-guns are fired while the remains are being borne to the place of inter- ment; but the number of such guns is not to exceed that which the officer was entitled to as a salute when living. After the remains are deposited in the grave, a salute corresponding to the rank of the deceased officer will be fired — three salvos of artillery, or three volleys of musketry. In the event of a flag-officer of the N'avy, whether of the United States or of a foreign country, dying afloat, and the re- mains are brought ashore, minute-guns are fired from the ship while the body is being conveyed to the shore. If it be in the vicinity of a military post, the flag of the latter is displayed at half-staff, and minute-guns are fired from the post while the pro- cession is moving from the landing-place. These minute-guns are not to exceed in number that which the officer was entitled to, as a salute, when living. During the funeral of a civil functionary entitled, when living, to a salute, the flag is displayed at half-staff, and minute-gims fired as before ; but neither salute nor salvos are fired after the remains are deposited in the grave. On the death of an officer at a military post, the flag is dis- plajT^ed at half-staff, and kept so, between the hours of reveille and retreat, until the last salvo or volley is fired over the grave, or, if the remains are not interred at the post, until thej'^ are removed therefrom. During the funeral of an enlisted man, the flag is displayed at half-staff, and is hoisted to the top after the final volley or gun is fired. All military posts in sight, or within six miles of each other, display their flags at half-staff upon the occasion of either one doing so. The same rule is observed toward a vessel-of-war. On all occasions where the flag is displayed at half -staff", it is lowered to that position from the top of the staff. It is after- ^ wards hoisted to the top before being finally lowered. '^'14. Should it occur that salutes which are due to any for- eign official or dignitary have not been provided for in the fore- going paragraphs, he may receive the salutes and honors which are awarded him in his own country. If time permits, however, special instructions from the War Department should be sought. APPENDIX. All weights and dimensions in tlie foregoing pages are given In English denominations. The only legalized unit of weight or measure in the United States is a troy pounds brought from England, by Captain Kater^ in 1827. This pound is a standard at 30 inches of the barometer ^nd 62° of the Fahrenheit thermometer. The standard avoirdupois pound is the weight of 27.7015 cubic inches of distilled water at 30 inches of the barometer and 62° F. The following table shows the relation between the troy pound and the avoirdupois pound : 7000 grains troy = 1 pound avoirdupois. 6760 grains troy = 1 pound troy. 175 pounds troy = 144 pounds avoirdupois. 175 ounces troy = 192 ounces avoirdupois. 437.5 grains troy = 1 ounce avoirdupois. In the United States artillery, tlie troy grain (7000 to the pound) is taken as the standard. 2240 pounds avoirdupois make a ton (long). 2000 pounds avoirdupois make a ton (short). The former is used by the English for all purposes. Both of these tons are in common use in the United States. Where precision is required, as in making contracts, &c., it is ■customary to state, in pounds, which ton is meant. A box 16 X 16.8 X 8 inches, contains 1 bushel. 12 X 11.2 X 8 inches, contains ^ bushel. 8 X 8.4 X 8 inches, contains 1 peck. 6 X 6 X 6.4 inches, contains 1 gallon, ^ liquid meas- 4 X 4 X 3.6 inches, contains 1 quart, j ure. Metric System. By an act of Congress approved July 28, 1866, the metric system of weights and measures is made optional in the United States, and the act provides that the tables in a schedule an- nexed shall be recognized ''as establishing, In terms of the weights and measures now in use in the United States, the equivalents of the weights and measures expressed therein in terms of the metric system ; and said tables may be lawfully used for computing, determining, and expressing, in customary weights and measures, the weights and measures of the metric system." (467) 468 APPENDIX. Schedule annexed to act of July 28, 1866. MEASURES OF LENGTH. Metric denom- inations. Yalues in metres. Equivalents in denominations in \ use. . Myriametre Kilometre 10000. 1000. 100. 10. 1. 0.1 0.01 0.001 6.2137 miles. ; 0.62137 mile, or 3280 feet and 10 In. 328 feet and 1 inch. 393.7 inches. 39.37 inches. \ 3.937 inches. f 0.3937 inch. 0.0394 inch. Hectometre Decametre Metre Decimetre Centimetre Millimetre 25.39954113 millimetres = 1 inch. 0.30479449356 metres = 1 foot. 0.91438348 metres = 1 yard. 1.6093149 kilometres = 1 mile. MEASURES OF SURFACE. Metric denominations. Yalues in sq. metres. Equivalents in denominations in use. Hectare •• 10000 100 1 2.471 acres. 119.6 square yards. 1550 square inches. Are ...•........«.•..«•....•«.«• Centare... .................. 1 square centimetre. 1 square decimetre.. 1 square metre 1 square metre 1 square metre ~ 1 square inch 1 square foot 1 square yard , 1 square mile 0.15500591 square inches. 0.107642993 square feet. 10.7642993 square feet. 1.19604326 square yards. 0.0002471 acre. 645.136(39 square millimetres. 0.092899683 square metre. 0.83609715 square metre. 2.58989447 square kilometres. MEASURES OF CAPACITY. Metric denominations and yalues. Equivalents in denominations in use. Names. No. of litres. Cubic measure. Dry measure. Liquid or wine measure. Kilolitre or stere 1000. 100. 10. 1. 0.1 0.01 0.001 1 cubic metre.... 0.1 c. metre 10 c. decimetres. 1 c. decimetre.... 0.1 c. decimetre. 10 c. centimetres 1 c. centimetre.. L308 c. yds 2 bus. 3.35 pks. 9.08 quarts 0.908 quart 6.1022 c. inch.. 0.6102 c. inch.. 0.061c. inch.... 264.17 gallons. 26.417 gallons. 2.6417 gallons. 1.0567 quarts. 0.845 gill. 0.338 fluid oz. 0.27 fluid dr'm. Hectolitre ... Decalitre . ... Litre Decilitre Centilitre.... Millilitre \ METRICAL EQUIVALENTS. 469 1 cubic centimetre (c. c) = 0.0610270515194 c ibic inches. 1 cubic decimetre = 61.0270515194 cubic inches. 1 cubic metre = 61027.0515194 cubic inches. 1 cubic metre = 35.31658074 cubic feet. 1 cubic metre = 1.3080215 cubic yards. 1 cubic inch = 16.3861759 cubic centimetres (c. c.) 1 cubic foot = 0.0283153119 cubic metre. lcubi<5 yard = 0.7645135 cubic metre. WEIGHTS. > Metric denominations and values. Equivalents in denominations in use. Names. Number of grammes. Weight of what quan- tity of water at max- imum density. Avoirdupois weiglit. Millier, or toimeau. Quintal 1000000. 100000. 10000. 1000. 100. 10. 1. 0.1 0.01 0.001 1 cubic metre 2204.6 pounds. 220.46 pounds. 22.046 pounds. 2.2046 pounds. 3.5274 ounces. 0.3527 ounce. 15.432 grains. 1.5432 grains. 0.1543 grain. 0.0154 grain. 1 hectolitre Myriagramme Kilogramme, or kilo Hectogramme Decagram.me.. ......... 10 litres : 1 litre 1 decilitre 10 cubic centimetres 1 cubic centimetre 0.1 cubic centimetre 10 cubic millimetres 1 cubic millimetre Gramme Decigramme Centigramme Milligramme Additional Metrical Equivalents. 1 surveyor's chain in metres = 20.11662 ... log.= 1.3035550 1 metre in surveyor's chain = Q.04971*... log.= 8.6964450 1 square foot in square metres.. = 0.09290*... log.= 8.9680221 1 acre in hectares — 0.40467*... lo^.= 9.6071100 1 square mile in hectares = 258.904 ... log.= 2.4132900 1 square metre in square feet... = 10.76410 ... log.= 1.0319779 1 hectare in acres = 2.47109 ... loo^.= 0.3928900 1 hectare in square miles = 0.00386*... log.= 7.5867100 1 cubic foot in steres = 0.02831*... lo(;.= 8.4520332 1 cord in steres = 3.62445 ... 102^.= 0.5592432 1 stere in cubic feet == 35.31561 .... log.= 1 .5479668 1 stere in cords = 0.27590*.... loo-.= 9.4407568 1 |?rain in grammes = 0.064798*.. log.= 8.8115680 To avoid negative characteristics, 10. has been added to the logarithms of the numbers marked * in the above table. 470 APPENDIX. Miscellaneous. Length. — Gunter's chain = 66 feet = 4 pales = 100 links of 7.92 inches. 1 fathom = 6 feet ; 1 cable-length = 120 fatlioms. 1 hand = 4 inches; 1 palm = 3 inches; 1 span = ^ inches. Solid. — 1 cubic foot = 1728 cubic inches. 1 cubic j^ard = 27 cubic feet = 46656 cubic inches. 1 reduced foot (board-measure) = 1 square foot X 1 inch thick = 144 cubic inches. 1 perch of masonry = 1 perch (16^ feet) long X 1 foot high X 1^ foot thick = 24.75 cubic feet ; 25 cubic feet has generally been adopted for convenience. 1 cord fire-wood = 8 feet long X 4 feet high X 4 feet deep = 128 cubic feet. 1 chaldron coal = 36 bushels = 67.25 cubic feet. Paper, — 24 sheets = 1 quire. 20 quires = 1 ream = 480 sheets. The units of capacity measure are the gallon for liquid and the bushel foi- dry measure. The gallon is a vessel containing^ 58372.2 grains (8.3389 pounds avoirdupois) of the standard pound of distilled water, at the temperature of maximum den~ sity, (39°.83 Fahrenheit,) the vessel being weighed in air at 62° F., the barometer standing at 30 inches. The bushel is a measure containing 543391.89 standard grains^ (77.6274 pounds avoirdupois) of distilled water, weighed as above The gallon is the wine-gallon, of 231 cubic inches, nearly ; and the bushel, the Winchester bushel, nearly. WEIGHTS AND VOLUMES OF SUBSTANCES. 471 Weights and Volumes of various Substances. METALS. SUBSTANCES. iirass^2inc 33 Brass, gun-metal Copper, cast plates Iron, cast gun-metal wrought bars Lead, cast rolled Mercury, 60° Steel, plates soft Tin Zinc, cast rolled CUBIC CUBIC FOOT. INCH. Pounds. Pounds. 488.75 .2829 643.75 .3147 547.25 .3179 543.625 .3146 450.437 .2607 466.5 .27 486.75 .2816 709.5 .4106 711.75 .4119 848.7487 .491174 487.75 .2823 489.562 .2833 455.687 .2637 428.812 .2482 449.437 .2601 WOODS. SUBSTANCES. Ash Cedar Chestnut Hickory, pig-nut shell-bark.... Lignum - vitse Mahogany, Honduras Oak, Canadian English live, seasoned- white, dry upland... Pine, yellow Spruce Walaut, black, dry.... Willow, dry..; CUBIC CUBIC FOOT. FEET IN A TON. Pounds. 52.812 42.414 35.062 63.886 38.125 58.754 49.5 45.252 43.125 51.942 83.312 26.886 5 35. t 66.437 64. 33.714 54.5 41.101 58.25 38.455 66.75 33.558 53.75 41.674 42.937 52.169 33.812 66.248 31.25 71.68 31.25 71.68 30.375 73.744 472 APPENDIX. MISCELLANEOUS. SUBSTANCES. Air Brick, fire mean Coal, anthracite bituminous, mean cannel , Cumberland , Coke Cotton, bale, mean pressed Earth, clay common soil, gravel... dry sand loose , G-ranite, Q,tiincy Susquehanna... Limestone Marble, mean Mortar, dry, mean Water, fresh salt Steam CUBIC rooT. Pounds. 137 102 89 102 80 94 €4 62 14 20 25 120 137 109 120 93 165 169 179 167 97 62 64 ,075291 .562 ^75 ,5 !875 ,687 ,5 ,5 625 125 312 75 .75 25 875 ,98 ,5 ,125 ,036747 CUBIC FJEET IN" A TON. 16.284 21.961 24.958 21.854 28. 23.609 26.451 35.84 154.48 114. 89.6 18.569 16.335 20.49 18.667 23.893 13.514 13.254 12.462 13.343 22.862 35.84 34.931 Alloys. Bronze Gun-metal. — 90 copper and 10 tin. Bell-metal. — 78 copper and 22 tin. Fine brass. — 2 copper and 1 zinc. Brass for parts of gun-carriages. — 80 copper, 17 zinc, and 3 tin. Sheet brass. — 3 copper and 1 zinc. Silver solder. — 4 silver and 1 copper; or 2 silver and 1 brass wire. Hard solder. — 1 zinc and 2 brass. Plumber'' s solder. — 1 tin and 1 lead. Tinner'' s solder. — 1 tin and 2 lead. Fewterer''s solder. — 2 tin and 1 lead. Fusible alloy. — 2 tin, 3 lead, 5 bismuth ; melts at 197°. Type-metal. — 11 lead, 2 antimony, and \ tin. German silver. — 40 J copper, 31 J nickel, 25^ zinc, 2^ iron. WEIGHT SUSTAINED BY SHEAR SPAR. 473 German silver for casting. — 60 copper, 20 zinc, 20 nickel, 3 lead. Pewter. — 4 tin and 1 lead. An alloy that expands in cooling. — 9 lead, 2 antimony, and 1 bismuth ; useful for filling small cavities in cast-iron. Bahhifs metal, for journal-boxes. — 9 tin and 1 copper. To ascertain the Weight that a Shear Spar will Sustain With- out Breaking. The case is that of a cylindrical beam inclined upward and supported at each end, the weight applied at a distance m from one end. For a square beam in this position the for- mula will be : Sld^ P ■VV= X -; in which m {I — m) c' W = the weight S= the value of the fOak S=50 timber for general use, or -J Y. pine S=50 iw.pineS=45 Z= the length between supports in feet. (A B.) d = the diameter or side of the beam in inches. (A E.) m = the distance in feet from either point of support to the point where the weight is suspended. c = the inclination of the shears or the horizontal distance between the heel and upper point of support in feet. (BC.) For a cylindrical beam the result must be multiplied by .78124. ~"b C Example.— R^y'm^ S =» 50, Z = 27^ d = 10% m = 2^, c =10, SZ3# then W = X .78124 = m {l—m) c^ 50 X 19683 X 1000 X .78124 2 X 25 X 100 19683 X 7.8124 = 154771. lbs. This is only calculated for a steady strain ; the result should 474 APPENDIX. be diminished at least one-half to allow for the surge of the fall around the capstan, both when hoisting and lowering. To ascertain the Strain on the Guys and Spars, From actual measurement of the ground, &c., construct a dia- gram as follows : AB. The shears at their ultimate inclination. AC. The guys. AD. A vertical line representing the weight suspended. A. C ,."" With any scale of equal parts lay off on the line A D the distance equal to the number of units of weight ; say, represent 25 tons by 25 inches; through the point E thus found draw E F parallel to A C. Then, the distance E F measured by the same scale will represent the strain on the guys, and A F the thrust on the spars. Precaution. In selecting spars for shears, it must be borne in mind that the strain on the shears is equal to the weight lifted plus the force r&- quired at the end of the fall to suspend the weight. Mensuration. Area of a triangle = base X ^altitude. Area of a parallelogram = base X altitude. MENSURATION. 475^ Area of a trapezoid = { "^^^^^ X ^ ^^^ «""^ «* P^^-^"«^' Area of a tranezium _/ divide into two triangles, an^ Area of a trapezium — ^ ^^^^^ ^^^^^ ^^ ^^^^ triangles. Circumference of a circle... = diameter X 3.1416. Diameter of a circle = circumference X .3183. Area of circle = (diameter) ^ x .7854. Area of sector of circle :*= length of arc x ^ the radius. Area ol segment ot circle.. = } '"'tVfif i?';£,T*^ '^'""'^ ^ { Jess area of triangle. {diameter of the two circles X difference of diameter, and> that product by .7854. Side of square that shall J diameter X .8862, or circumfer- equal area of circle =\ ence X ^282. Diameter of circle that f shall contain area of a -j side of square X 1.1284. given square = (. Area of an ellipse ={^"'^854. °* ** ''''° '''*'"'"''^ ^ Area of parabola = base x f altitude. {sum of its sides x perpendicular from its centre to one of its* Sarfaceof cylinder ={:"Zdj^,^'-^ '•"'^' ^ Contents of cylinder := area of ends X length. Surface of sphere = diameter X circumference. Contents of sphere = (diameter) * X .5236. Surfaceofpyramidorcone. ={-;—--«.«''>-« >^ ^ZTe!L!'L!:I!^^l.Z _{ area of base X J altitude. c e t*i. t ( sum of circumference at both. Surface of f nistrum of cone 1 ^^,^^^ , ^.^^ _^ ^^^^ ^^•Py^^^«^'^ =1 of both ends. ^ {multiply areas of two ends to- gether and extract square root^ Add to this root the two areas^ and X i altitude. 476 APPENDIX. -Contents of a wedge = area of base X ^ altitude. Contents of a ring ^ftliickness + inner diameter X ^ X square of thickness X 2.4674. To ascertain the distance to an inaccessible object ; as, for in- ■stance, the breadth of a river : {Fig. 4, Plate 75.) 1st. The line A B (the distance to be determined ) is extended upon the bank to i>, from which point, after having marked it, lay off equal distances, CD and C d ; produce B to b, making Cb = OB; then extend the line db until it intersects the pro- longation of the line CA at a. The distance a 6 is equal to A B^ or the width of the river. 2d. Lay off any convenient distance, B C, perpendicular to AB ; erect a perpendicular, DC, to AC ; note the point D -where it intersects A B produced ; measure BD ; then — BC^ AB BD' Capabilities of the Horse. The average weight of a horse is about 1000 pounds; for artil- lerj^ purposes he should average 1100 pounds. In ranks he 09CU- pies a front of 40 inches, a depth of 10 feet ; in a stall, from 3.5 to 4.5 feet front. The load for a light-artillery horse is 700 pounds, including •carriage ; for heavy field artillery, 1000 pounds, including car- riage. This is less than that allowed for the ordinary horse in ■civil service, in consequence of bad roads, scant forage, and frequently forced marches. Including the weight of carriage, four horses can draw, on roads such as are considered in America good., 3000 pounds ; six horses, 4000 pounds; eight horses, 5000 pounds ; and ten horses, '6000 pounds. This allowance diminishes rapidly as the roads become bad, A horse will pack from 250 to 300 pounds, 20 miles per day — eight hours. Tlie mule is superior to the horse as a pack ani- mal. An ordinary march is about 15 miles per day of eight hours, depending upon the state of the roads, condition of the horses, and various other circumstances. The rate of march, with liorses starting fresh and resting for a few minutes each half-hour, would be 2.5 miles for the first hour, 4 miles for the next two hours, and 8.5 miles for the remaining five hours. A horse carrying a rider marches, at a walk, at the rate of ■3.75 miles per hour; at a trot, at the rate of 7.50 miles per hour; ;at a gallop (slow), at the rate of 11 miles per hour. CAST-IRON BALLS. 477 A horse requires, per clay, 4 gallons of water and 12 pounds of short and 14 pounds of lon^ forage. Iron. Strength. The mean strength of American wrought-iron is 55,900 pounds to the square inch; of English, 53,900 pounds. The working strain is from one-sixth to one-fourth the mean strength. The ultimate extension of wrought-iron is ^^th part of its length. Test quality. If the fracture gives long, silky fibres of leaden- gray hue, fibres cohering and twisting together before breaking, the iron may be considered tough and soft. A medium even grain, mixecl witli fibres, is a good sign. A short, blackish fibre indicates badly-refined iron. A very fine grain denotes a hard^ steely iron., apt to be cold-short, hard to work with the file. Coarse grain, with brilliant crystalline fracture, yellow or brown spots, denotes a brittle iron, cold-short, working easily when heated and easily welded. Cracks on the side of a bar denote hot-short iron. Good iron is readily heated, soft under the hammer, and throws out but few sparks. Steel. The tensile strength of good steel is 120,000 pounds per square inch. The properties are ; After tempering, not easily broken ; welds readily ; does not crack or split; bears a very high heatf can be hardened after repeated workings; is magnetic, and, as distinguished from iron, when once magnetized does not lose its- polarity at ordinary temperatures. CAST-IRON BALTiS. DiATvrETER. "Weight. Dtatvtrter. Weioht. Diameter. "Weight. Inches. Lbs. Inches. Lbs. Inches. Lbs. 2 1.09 5 17.04 8 69.81 2J$ 2.13 m 22.68 S^ 83.73 3 3.68 6 29.45 9 99.40 m 5.84 6Ja.v». lo8, JIC. >LXT£ 3 S*»-,|»|',.',a^J3>2; ' f:4i.'i\$.)tt^ 3(19, C 1^0.96, 3)«l. "Plate 4. Chok.«e , Dvl. SfcA ~ 'Ji]».'<-c.42.4-*.4-r.4^.5C. ' ' >,».v«.JO«'- ^o*''%<5)'*•2^^• %^ » "fl ; "' Chase, De-l. ]o.62 *Plate Z, TPl^te S. C\]JK9«, jDcl.. o«t — "I*"!-"' ss.bz. to. t c c c Plate 9. CI)a,«*,!DfcL. ' 3i*i -i. f» . 20'. |9cx.V.'££*.' ' "Plate 10. . -'C-.*- Fcg^.2, JFlg-.S ' 1 1 1 [- — i n n n _ U I: y 1 Fi^.^. Cl^a.»»,l>«,l. I»ar«. 2£5.2«.6.22r.228. < < > t "Plate 11. •J "i^S ^ I • ^ ^ ^ •"^ ■* "^ Ci^asfc.Dtl. See,-j9]». 83, >. :d7.l)&9. 190.' ' ' y y y , •, y' \ ' o^' » »,» > J,' ^LATE 16, Tie-. 1. Cljase,De\, ;.a.it. 4_}|.,4ia. 4-^i.e; , , , Kate iZ. C/^ase , Del See-)a>. 170.171. 177. >o^rs. 379.38J.390. IPLKTE 18. e^ — I i^Pk eunOuck. Q% c:^ I W- £. S1ad\ yv /<•tM — tk-rUttttwrnrM Ikuimitrrtt T^u. Cl^^ase',Dcl. Se,e-|».^O0. ]ja,r. 416. jPlate 19, Chase ,Del ' 2 0^.207. ko a. li\Z. |occrs.4 26.4-2r.4-33. 436.4-39. f48. Jig-. 1 . 'f(n'((!(ff'(f(ffl((**!f""""«"" "'"'"""""' "Plate ZO. MiimiM iininn 3ca Ecmr CfjO/SesDel. '>cc^^ 44?-. 4'48: ' J'late 21 Fig-.l. V~- J J n Chase J Del. Plate 22. Tig-.?. FiQ".6. -.'i'- ^^i^ v-J ."*' '• C I? as e J Del See. -T)]:.'^!^. -2 20.- - " ' 2 a I, 2 SO. ( ( , t JpLATE 2r3 Chase, Del. Kate 24. 2^^^^^^^i^i^^S^^^SS^S^g^^^cv.476 Plate £5 CROMMtr tssssaa^ TWO HALF HiTCHBi , Clove HircH 80WLI NE . Round tvh.n and Two HALF HITCHES . SQ.UARE FiSHfRNAN L> .S CkXRICK BEND Cliase J Da Tlate 26 SHCCP SHANK Aru-horKnot. MARLINSPIKE HITCH ^TwrnrnnmrifiTTirT NIPPER OR RACK L»SHINC Scrtw STRAP. POINTING-. APPLICATION BerlcH Knot. Cl?ase ,Del. Plate 27. Met'rtrtg Ihot . •>■>■> •> ■> -^ * -i •>•* ^ ) Cli^ase, Del. See — ]3 . 2 3 r. '\>cL^':A-Y6: ik, se,q . Ilate 28 e"x»"C TO Move A HEAVY GUN FROM A vessel's DECK. JfCLYVSi)- JCitot Cnase , Del Plate 29 sun. Sty-cc/^ . Tvoiv Bh>cks •fiii^Uj Ucublc for ht.u,)iy 9«iii Clicks e 5 Dftl Se.e ->:-2S^;|.o..-.4-82 r.^^-^--, Plate 30 W/ii/j (^uikTackle JJCoLLSLJtl Buitbii Cliase ,Del. Sea>.-,io,2 3 8.i.c.r.48e Plate 31. Cl|^ase,Del. -rr-' , ^ee -V.24e:]ia:v.'485i ' Plate 32 Chase J Del. See-).I..243.245.253. 25Z. 259. ^«^f. 487. 4-90. 5o2 . 5o6 .510. < < I <. , c t <- Plate 33. C)lia,5e,DcX. 5ee-]*.£52.]»tcv.50l, Tlate 34. <-jo*is^ww ww p y !w Clictr«. 5^0 E. 508 Plate 35. TRUCK WAGON •".. • '^ r-.^ — - f ^ i^ •^ '^^ i/HZi' - RAILWAV TRUCK . '"i^Tl ^ rrt--VTi:*/ Sec ~>: 2&0:]o"«.v.5l^ Plate 36. C/jaS6,T)el, See- 26l.]9our.5l6. Plate 37, • i > , » 1 1 i • J . , > > , J Chase J Del. TiQ\Z. Plate 38, n □ life:: i 0' % n D 1 Cl|ase_,Del. See->.262.26S. E70. >«.r5. 5/7. 52o. 530-1. "Plate 39. Chasii J Del. SU^)^\H^r:yc..,S'cl' "Plate 40. ^ee l-J]i.Z6^.].cl-,:S.2.^i }^C Kate 41. Plate 42 Tig. I -J -~T- Clja3e,T)eI. Set — ]-• ?7^ '* 2r6. "Plate 43, Kg-. 2. m^^^ • ^^^^ J i > \ > > » > C)|a3e , Del. Kate 44. Fig'.l. Kg'. 2 s-^rx* ,- •-?--. ;m<-' > J 1 ) Chase 5 Del-. See-». 2r5(-o 2^6. J^LATE 45, Tiff. 1 t i * » t » Clias6,DeL. $«,«._]»],. 273 to 276. wvs- 5 34. S3 5. Tlate 46. XI - 27$>.>a.7-.539. Kate 49. Chase, Del See-lb.^/'9.].ccr.539. c c f c t '~ t Plate 50, Cimse ,X)eI J?late51 ChaiQyOeX. '•> / . ' ,29P. Kate 5Z 3^.e -^>'' 2:8F%3.:54/. Tlate 53. M\-7v^^l'*^^^> ^^{ Plate 54. -Fig. 4. R^.2. \ Fig: 3. I- I puinzEZlDli • Uf Set -t>..30Q ?dTra6'^. IJOCT. 50 I . JpLAT£ 55. Cljas6jDel. See "->].. 303.3(3^308. Plate S6. C/]u-»e 5 Del Set-./^).. 3 17. 3 2 9. 3 30. c t ( < ^ ' , "^ Kate S7. Yi^A. Pio-.S. Txg-.S. Cl]a.s e , Del . "Fig-.4. <; \jr^yr.. 3e,^ ^yh rS^6 IS^T: 3&». ycJs.OoA-. 605": 6u6. 608. 6'0. Plate58. E A~ - ~D '^r v>^i .-Pi. Fio-.l '=C=^ ^vr^ '''*"*''''*W»w«w*w/^ ^o K^.3 ''"'^y-:^^^^' "'^ Fio-.4. «.vs.6ll. 6(3. Plate 59. T\OL>V . Tvcf.t Tig. 2. wmw;//////// Choi.se,T)eX. ^--U Plate 60. Tig.l. tl IZ IS 7x0'. 2 •VIOLTV. Fio. 6 Fio^^ Fig.8 C/icLse jDel See. —y^.Z79. 380.381. 6 ^ 5 . 'i> '^. b . Plate 61 CI|a,Sft,T)el. See-». 384.385. 387. >ctvs. 629.63 3.634. 638. TD jfLATE GZ -rr-i-^w^J See -]ov38§ . )5aV?^3 6. Plate 63. B B S\ » " » '> J) "" » » J See~]o. 388.]oar.636. ' c c c c -t c <. ( • c '^ Plate 64. TT B^ pi^S^a^'p CliasejDel. See — I*. 3G3< ']>oii::LEa i^ Pig. 2 FiUnL^ /tooiiu- J^Cauoout. Lft-b Cf|a5e^De"l. See ~]a]o. 390-1. Kate 66. Cf|cose,Del. See-J.J». 39e.39S. y>crs. 637. 638 Plate 6t. Kg. 4. Tig. 5. i F^^-^ >J J JJ , - t . t ' J i I Cnase^DeL. See-W.. 394.395.397. >a,v6.fe39.fe4-|.643. Tlate 68, B ^ rrr;r C-; Cl^ase jDel. 7oars.546T47. J?LAT£ 69. Fxp.l. '8 M4^^ ■^c ' Cf|atfc J Del. TDars. 648.649. "Plate 70. C/^otse^Del See ->. 4-04. -pan: 650. Plate 71. \^ "%^ y ^'^g"-^- klMliM/^"' Chase, Del. See ->. 4-08. 4-1 3. >ccr4.657.664; ( ( c c TpLATE 72. i e '{ S S S ( f Pig. 3. / \ y ] O 0/ 0\ O / \ 6 d Cy ©\A: , .^ •<,--• Chase, Del. See-».4I9.4-Z9. "Plate 73, Txo.l TigA Chase, Del, Kate Z4. rig.2. O Tig.B. lV'^S6r'3'9'r 44-0.445. f9cxns.67Z-78- I/.'; ^ •. Chase ^ Del. t>ar. 690. >>. 4-76 A/3/»e.ixau . Plate 76. V^ » » * » * > » 1 ' * » ■' . » * •*_> » » 'Sec -'p: ^^i^t ■j^o,-!*. 5 S o • 'Plate ZZ. tg: A 7ft,V'"xVV>\<\VVA\\\VW\\VVVVVVVWVVV^V\">.VVW\V fiction, tliro Liitt m . w CKase.Del. ;See - hcLCr-e^ ^SS.A 14 DAY USE RETURN TO DESK FROM WHICH BORROWED LOAN DEPT. This book is due on the last date stamped below, or on the date to which renewed. Renewed books are subject to immediate recall. iiumfQ ^ _ ^ ^ . — t^"**^ "■ 0^ %^ m iwn n9 1*^^° vJUlM \j ^ i^*-" - •- ' ^ -. . ; f.«r ] 6 1^59 LD 21A-50m-8,'57 (C8481sl0)476B General Library University of California Berkeley U.C. BERKELEY LIBBABI coDssastbi M44844 T5 THE UNIVERSITY OF CALIFORNIA LIBRARY