CORNELL UNIVERSITY LIBRARY FROM E.^eal Cornell University Library U167 .W13 1896 The service of security and information olin 3 1924 030 723 369 Cornell University Library The original of this book is in the Cornell University Library. There are no known copyright restrictions in the United States on the use of the text. http://www.archive.org/cletails/cu31924030723369 NOTICES OF THE PRESS. "Based upon a careful study of the best authorities of both hemi- spheres and upon independent examination of noteworthy examples in the militairy history of om- own country as well as Em-ope." — The Nation. "Should be in the hands of every one desiring to know his pro- fession." — Army and Navy Journal. "Full of suggestions valuable to even an experienced officer, and invaluable to one for the first time called to a position of danger and Immediate exercise of judgment." — Army and Navy Register. "A praatical and common-sense view of the subject worthy of adoption in our service." — Broad Arrow, London. "This volume ought to meet with a hearty welcome from all arms of the service. * * * j^ meets a want which has long been felt."— Journal of the Military Service Institution. "It is a drill-bools in the best sense of the word."^0Mr»ai of the U. 8. Artillery. "It should be a matter of pride to all ofBoers to have an authorized American work of such excellence on this suhject." ^Journal of the V. S. Cavalry Association. THE SERVICE OP Security and Information ARTHUR L. WAGNER, Captain, Sixth Regiment of Infantry, U. S. Army ; Instructor in the Art of War at the U. S. Infantry and Cavalry School ; Gold Medalist of the Military Service Institution of the United States; author of "Organization and Tactics," "The Campaign of Koniggratz, ' ' etc. THIRD EDITION. Officially authorized by the War Department as a Standard in the ^Examination of Officers of the Regular Army for Promotion. HUDSON-KIMBKRI,Y PUBLISHING COMPANY, 1014-1016 Wyandotte Street, KANSAS CITY, MO. 1896. /^/ JJTf <^ Copyright by ARTHUR t. WAGNER, 1893 and 1896 ' Cmcui,AR, ) HEADQUARTERS OF THE ARMY, C ' Adjutant-Genbral's Office, No. 17. ) Washington, June y, i8g$. With the approval of the Secretary of War, the following is published for the information and guidance of the Army: '■The Service of Security and Information," by Captain Arthur L. Wagner, 6th Infantry, is announced as an authorized text-booli, in connection with the system of examination to determine the fitness of officers foo- promotion, prescribed in General Orders, No. 80, of 1891, from this office. By command of Major-Genkrai, Schofield : R. WILLIAMS, Adjutant-General. Officiai, . Assistant Adjutant-General. PREFACE TO THE THIRD EDITION The gratifying reception accorded to the first and second editions of "The Service of Secui'ity and Information" encourages the author to hope that the revised edition of the book novF presented may not be unveelcome to the officers of the Regular Army and the National Guard. Profiting by the liind criticism of his brother oflicers, and by his own experience in using the worli for more than two years as a text- book at the U. S. Infantry and Cavalry School, the author has made a few changes in the text, which, it is believed, will meet with approval; but these clianges are nedther so many nor so great as to effect any radical alteration in the work. The author desires here to express his thanks to Captain Eben Swift, Fifth Cavalry, First Lieutenant A. L. MUls, First Cavalry, and First Lieutenant J. T. Dickman, Third Cavalry, assistant instructors in Art of War at the U. S. Infantry and Cavalry School, for valued suggestions in the revision of the book. XJ. S. Infantry and Cavalry School, Fort Leavenworth, Kansas, February 1, 1896. PREFACE. PREFACE TO THE FIRST EDITION. This book lays claim to no other merit than that of being an earnest attempt to meet the demand, often expressed, for an Ameri- can text-bools on the subjects herein discussed. Many of the features of the service of security and information are common to both hemispheres and to all armed forces, whether savage hordes or highly organized armies. Other details of the same science vary with the topography, the organization of the army, national characteris- tics, and the nature of the enemy encountered. It follows, therefore, that a text-book on this subject might be admirably adapted to the requirements of European officers and at the same time be In some respects quite unsuited to om- needs. English, French, and German military writers have written so voluminously on all tactical subjects, that the author has found a wealth of valuable books at hand for consultation; and he has dis- covered, on most of the important points, a gratifying unanimity of opinion on the part of writers of different nations. The aim of the author has been to select the best established theories of European tactical authorities, to illustrate them by a reference to events in otir own military history, and to apply to them the touchstone of Ameri- can practice in war. To this end he has submitted his manusciT.pt to several officers of high ranli and distinguished ability, who have criticised it in the light of their own extensive military study and great experdence in actual warfare. The author is at a loss for an adequate expression of thanks to Brigadier-Gteneral Thomas H. Ruger and Brigadier-General Wesley Merritt, U. S. A., for the valuable criticism, comments, and notes with which they have favored him, and by means of which he has been enabled to place upon his work the best stamp, as it were, of American experience in war. He desires also to express his obliga- tions to Lieut.-Col. H. S. Hawkins, 23d Infantry, Lieut.-Col. Guy V. Henry, 7th Cavalry, Major H. G. Hasbrouck, 4th Artillery, Major 0, C. C. Carr, 8th Cavalry, and Major J. B. Babcock, A. A. G., for valuable information and comments. To Lieut.-Ool. Henry, Cap- tain E. S. Godfrey, Tth Cavalry, and First Lieutenant Thomas Cruse, Cth Cavalry, the author is indebted for most of the information on which the chapter on "Indian Scouting" is based. To Colonel B. F. Townsend, 12th Infantry, Commandant of the U. S. Infantry and Cavalry School, in compliance with whose order this work has been written, and whose steady and consistent encouragement has accom- 8 PREFACE. pauied it from its inception to its appearance in these pages, the author's thanks are especially due and are gratefully tendered. A word in regard to the form in which this book makes its appear- ance may not be out of place. There is a fashion in books, as in all other human products; and the shape in which some of our most valuable military manuals have appeared would seem to indicate a tendency to sacrifice everything to the fancied benefits of portability; military books being printed in small type to reduce them to a proper compass to fit the pocket — in which, by the bye, they are never car- ried. It is not clear that this fashion has anything to recommend it; while anyone who has noticed the impaired eyesight of many of the graduates of our officers' schools must find much to condemn in a typographical style which seems designed mainly for the benefit of the oculist. It is hoped, therefore, that the typographical dress of this volume will prove a welcome innovation. The plates with which this work is illustrated are, with a single exception, from drawings made by Lieutenant C. B. Hagadorn, 23d Infantry, whose skill and accuracy in such work are well known, and to whom the author desires to express his obligations. A list of books consulted in the preparation of this work is given below. Where the author has felt under special obligations to any particular work, acknowledgment has been made in the text or in a foot-note. In many cases, however, the words of several authorities on the same subject are so similar that it seemed' impossible to ren- der tribute to any particular one. The author accordingly takes pleasure in expressing his obligations generally to all the works mentioned in the following list; more especially to De Brack, Riistow, Von Minis, Clery, Shaw, Wolseley, and the Guide Manuel du Chef de Patrouille. Cumberland, Md., March 1, 1893. IvIST OF BOOKS CONSULTED IN THE PREPARATION OF THIS WORK. Apergus sur Quelques Details de la Guerre, Bugeaud. Artillery Drill Regulations (U. S.). Art of War, Jomini. Avant Postes de Cavalerie L6g6re, De Brack. Battles and Leaders of the Civil War. Campaigns of Stimrt's Cavalry, H. B. McClellan. Catechism of Military Training, Marryatt. Cavalry Field Duty, Von Mirus (tr. by Russell). ■Cavah-y Drill Regulations (U. S.). Cavalry, Regulations for the Movements and Instruction of (British). Cavalry in Modern War, Trench. Conduct of a Contact Squadron, De Biensan (tr. by Bowdler-Bell). PREFACE. 9 Duties of the General StafE, Bronsart von Schellendorf. Dienstunterrieht des Infanteristea, Von Waldersee. Elements of Modei-n Tactics, Sliaw. Esprit des Institutions Militaires, Marmont. Extracts from an Infantry Captain's Journal, Von Amim (tr. by East). Guide Manuel du Chef de Patrouille. History of the Crimean War, Hamley. History of the Peninsular War, Napier. History of the War with Mexico, Ripley. Infantry Drill Regulations (U. S.). Infantry Fire Tactics, Mayne. Instruction for Cavalry, Von Schmidt. Johnston's Narrative. Journal of the Military Service Institution of the U. S., various volumes. La Petite Guerre, Riistow (tr. by Savin de Larclause). Letters on Cavalry, Prince Kraft zu Hohenlohe Ingelflngen. Life of Andrew Jaclison, Panton. Mgthodes de Guerre Actuelles, Pierron. Minor Tactics, Clery. Maximes de Guerre, Napoleon. Memoirs of U. S. Grant. Memoirs of W. T. Sherman. Memoirs of P. H. Sheridan. Napoleon's Expedition to Russia, S6gur. Official Records of the War of the Rebellion. Operations of War, Hamley. PrScis of Modem Tactics, Home. RSglement sur le Service des ArmSes en Campagne, De Savoye. Service d'Exploration et de Sur§t6, Bonie. Soldiers' Pocket Book, Wolseley. Strategic Service of Cavalry, Bowdler-Bell. Strategischer Kavalleriedienst, Von Widdern. Strategy and Grand Tactics, Dufour. ' Studies in Troop Leading, Verdy du Vernois. Tactical Deductions from the War of 1870-71, Boguslawski. Tactique de Pfirizonius. Tactique des Renseignements, Lewal. The Army in the Civil War ("Scribner Series"). The Franco-German War, Borbstaedt (tr. by Dwyer). The Franco-German War, Von Moltke (tr. by Bell and Fischer). The Nation in Arms, Von der Goltz. War, Clausewitz. War, Maurice. lO CONTENTS. CONTENTS. PRELIMINARY DEFINITIONS Page 14 CHAPTER I. INTRODUCTION. The punctilio of private combat not applicable to the operations of war. — Condition of an army taken by surprise. — Security and in- formation inseparably connected. — Information necessary for a com- mander. — How obtained. — Exceptions in former wars. — Kind of infor- mation considered in the subject of tactics Page 17 CHAPTER II. THE ADVANCE GUARD. Division of a column of troops on the march. — The duty of the advance guard.— Its objects.— Its strength.— The several parts of the advance , guard. — The formation of the advance guard. — Distance from the main body. — The commander of the vanguard. — Staff officer with vanguard.— The commander of the advance guard.— Halts.— Sig- nals. — Compliments. — Cavali'y advance guard. — Its formation. — Ad- vance guard of all arms. — Formation modified by terrain. — Encounter- ing the enemy. — Advance guard of a division. — Advance guard of an army corps. — Flank guards. — Advance guard in a retreat. .. .Page 22 CHAPTER III. OUTPOSTS. Definition of outposts.— Historical instances of evil results of neg- lect of outpost duty.— Duties of outposts.— Subdivisions of the out- posts.— Two systems of outposits.— Position.— Strength.— Composi- tion.--Distance of outposts from the main body.— The commander of the outpost.— Sentinels and vedettes.— Connecting sentinels.— The picket sentinel.— Examining posts.— Detached posts.— Pickets.— Sup- ports.— Cossack posts.— The reserve.— The outpost at night— Outposit patrols.— Visiting pati-ols.— Reconnoitering patrols.— Strong patrols.— Posting the outpost— Defense of the outpost.— Relieving the out- Post Page 56 CHAPTER IV. RECONNAISSANCE. Importance of reconnaissance.— Kinds of reconnaissance.— Recon- naissance in force.— How conducted.— Objections.— Historical in- stances.— Special reconnaissance.- Historical instances.— Patrolling. CONTENTS. 1 1 —Exploring patrols.— Small Infantry patrols.— Oomposition.—Prep- aratlon and mspectlon.— Signals.— Formation of the patrol.— Con- duct of the patrol. — Encountering the enemy. — Inhabitants. — Guides. —Reconnaissance of different liinds of ground.— Cross-roads.- Heights.— Deflles.—Bridges or fords.- Woods.— Inclosures.— Houses.— Villages.=-Cities and towns.— Reconnaissance of the enemy in posi- tion. — Reconnaissance of the enemy on the march. — Signs and trails.— Reports.— Strong infanitry pajtrols.— Expeditionary patrols.— Prisoners.— Harassing patrols.— Flanli pati-ols.- The advance guard passing through a town. — Cavalry patrols. — Historical instances.— Connecting patrols.— Pursuing patrols.— Cyclist patrols.— Balloon re- connaissance Page 107 CHAPTER V. THE CAVALRY SCRBJBN. Screening and reconnoitering duty in the Napoleonic wars.— Re- vival of the duty in the War of Secession. — The eavaJry screen in re- cent Em-opean wars.— By whom the duty may be performed.— Dis- tance of the screen from the army. — Frontage of the sa-een. — Forma- tion of the screen. — Typical formation of a cavalry screen consisting of a brigade.— Horse artillery with the brigade.— Patrols.— Bonie's points. — Duties of the scouts. — The Uhlans in 1870. — Otficers' patrols. — German patrols after Spicheren. — Battle of Tom's Brook. — Separa- tion of the duties of security and information. — Transmission of in- teUigence.-^CoJitacrt and figbtinig.— Buford at Gettysbm'g.— Protect- ing the infantry. — Siezing important points. — Battle of Hoover's Gap. — Foraging. — Connecting posts. — ^A regiment as a screening force. — Conclusions Page 165 CHAPTER VI. REAR GUARDS. Effect if a defeated army be vigorously pursued.— Vigorous pur- suits not often made. — Duty of the rear guard. — Ney's method.— Strength of the rear guard.— Morale.— Oifensive returns.— De Fezensac at Smolensk. — Lee at Boonsboro. — Commander of the rear guard.— Distance from the main body. — Formation and composition of the rear guard. — Typical formations. — Withdrawal from action. — Commimica- tion between the several parts of the rear guard and with the main body.— Protection of the flanks.— Riistow's intermediate body.— Con- tact with the enemy to be preserved. — ^Defiles. — Negative measures.— Johnston's retreat in 1863. — Sick and wounded. — Halts. — Retreating by parallel roads. — When line of retreat is changed. — Rear guard in a retrograde movement which is not a retreat. — Rear guard in a friendly country.— In a hostile couBtry.— The rear guard in a forward march. Page 197 12 CONTENTS. CHAPTER VII. SPIBS. Military and civilian spies. — Wlien the services of spies are most valuable. — Persons VFho should be selected as spies. — Qualities requi- site in a spy.— Compulsory espionage.— Double spies.— Concealment of messages. — Spies as a check upon eacli other. — How spies should leave and return.— What a spy should report— Means of identification.— Use of the telegraph. — Precautions against enemy's spies. — The detec- tion of spies. — Their search. — The management of the secret service. Page 223 NEWSPAPERS. Their importance in war. — Newspaper correspondents "the plague of modern armies." — Control of correspondents. — The press censor. — Not merely the great newspapers that betray information.— Means of utilizing reporters. — Punishment for indiscreet or mischievous publi- cation Page 233 CHAPTER VUI. ORIENTATION AND MAP-READING. Definition of orientation.— Orientation by compass.— By observing the sun. — Use of a watch as a compass. — Orientation by observing the moon.— By observing the North Star.— By maps.— By indications.— Practice in map-reading.— Measuring distances on the map. .Page 236 CHAPTER IX. INDIAN SCOUTING. Apaches as small infantry patrols.— Scouting methods in Arizona. — SkiU in selection of posirtions and In defensive dispositions.- The Sioux scout.— Crook's march from Fort Fetterman.— Scouting methods of the Sioux.— Long-distance reconnoitering.— The Sioux camps.— The tactics of the Sioux.— Knowledge of geography and topogi-aphy.— Observations Page 242 APPENDIX I. Advance guard drill (Infantry).— Advance guard drill (Cavalry). Page 249 APPENDIX II. Questions for General Review Page 257 I^^'^^X Page 283 ILLUSTRATIVE PLATES. 13 ILLUSTRATIVE PLATES. Outpost Line, Showing Changes Made at Night. .Frontispiece. Facing Page. 1. Company of Infantry as Advance Guard 27 II. Permissible Formation of a Company of Infantry as Ad- vance Guard on an Open Plain 31 III. Battalion as Advance Guard 32 IV. Troop of Cavalry as Advance Guard 88 V. Order of March of a Division Acting Independently 48 VI. Regiment of Infantry as Outpost for a Division 61 VII. Squadron of Cavalry as Outpost for a Cavalry Brigade. ... 64 vm. Comparison of Cossack Posts with the Picket System 86 IX. Pati-ol System of Outposts 94 X. Patrols 120 XI. Advance Guard Entering Franklin, Tenn 150 XII^ Cavalry Screen Consisting of One Brigade 172 XIII. Cavalry Screen Consisting of a Brigade on Two Roads . . . 176 XIV. Company of Infantry as Rear Guard 20G XV. Troop of Cavalry as Rear Guai-d 208 14 PRELIMINARY DEFINITIONS. PREI.IMINARY DEFINITIONS. A6oHs— Rows of felled trees, with the smaller branches lopped off, and the others sharpened and turned towards the enemy. Base— "A base of operations is the portion of country from which the army obtains its reinforcements and resources, from which it starts when it takes the offensive, to which it retreats when necessary, and by which it is supported when it takes position to cover the country defensively. The base of opei-ations is most generally that of supply— though not necessarily so, at least as far as food is concserned. "—<7ommi. Billet — Quarters provided for troops in private houses, barns, etc. Soldiers billeted generally obtain from the inhabitants food and drink for themselves and forage for their horses; payment for these supplies being usually made at the rates and in the manner prescribed in regulations and orders. Bivouac — A temporary place of repose for troops, in which they are sheltered by shelter-tents, bowers, or improvised shelter of any kind, or sleep in the open air. A camp differs. from a bivouac, in that the men are sheltered with regular tents. Troops are cantoned when sheltered in huts or billeted in villages. Commtinications — The routes (roads, railroads, etc.) by which an army communicates with its base, or by which the several parts of an army communicate with each other. Compliments — Ceremonious marks of respect paid by officers and soldiers to their military superiors; such as saluting, standing at attention, etc. Containing Force^A body of troops charged with the duty of hold- ing In check a body (generally numerically superior) of the enemy, while the main efforts of the army are directed against another portion of the hostile force. Depth— The space occupied by a body of troops from front to rear. Distance— The space between bodies of troops, or individiial soldiers, from front to rear. Escort Wagon^-A four-horse wagon, lighter than the "army wagon." Front— The extent of ground occupied by the front rank of a body of troops in any formation. Glacis— A mound of earth, with a gentle slope to the front, thrown up a few yards in front of the ditch of a fortification. Impedimenta— Bagg&ge, and. In general, anything accompanying troops, which tends to impede the celerity of their movement. Interval— The lateral space between bodies of troops or individual soldiers. PRELIMINARY DEFINITIONS. 15 Morale— The condition of troops as to discipline, bravery, confidence, or discouragement, etc. Provost-Guard — A guard under the orders of a provost-marshal. Provost-Marshal — An officer attached to the headquarters of the com- manding general to superintend the police of the army; to provide for the protection of the inhabitants, of the country from pillage and violence; to preserve order among camp- followers; to take charge of stragglers, prisoners, and desert- ers; and to superintend the secret service. Shrapnel— GnUed the "man-lsilling projectile." A shell filled with bul- lets, and having a bursting charge only sufficient to break the ease and release the bullets, which then move forward with the velocity which the projectile had at the moment of bursting. Strategy— The art of moving an army in the theater of operations with a view to placing it in such a position relative to the enemy as to increase the probability of victory, increase the consequences of victory, or lessen the consequences of defeat Tactics — The ai't of handling troops on the field of battle. Terrain — The topography of a field, oonisidered especially in its rela- tion to tactical operations. Theater of War — "The theater of war comprises aU the territory upon which the parties may assail each other, whether it belong to themselves, their allies, or to weaker states who may be drawn into the war through fear or interest. When the war is also maritime, the theater may embrace both hemispheres. * * * The theater of war may thus be undefined, and must not be confounded with the theater of operations of one or the other army." — Jomini. Theater of Operations — "The theater of operations of an army embraces all the territory it may desire to invade, and all that it may be necessary to defend." — IWd. Vedette — A mounted sentinel. CHAPTER I. INTRODUCTION. It is pardonable to be defeated, but never to be taken by sur- prise. — Frederick the Gi-eat. If opposing armies could marcli unmolested to a desig- nated battle-field, as the knights of old repaired to their tournaments, the military problem would consist simply in drawing up the forces in order of battle, and nine-tenths of the difficulties of the art of war would be eliminated. But just as the code of ethics which governs the actions of indi- viduals is varied greatly when applied to the diplomacy of nations, so the chivalry and punctilio of private combat are necessarily lacking in the operations of war. It is the duty of a commander to assail the enemy under circumstances most unfavorable to the latter and most advantageous to himself; to catch the hostile army astride of an unfordable stream, or divided by an impassable obstacle of any sort ; to assail the communications of his opponent while covering his own; to surprise him, and, in brief, to take advantage of the unfortunate position or unskillful dispositions of the foe, and to guard against being similarly assailed himself. An army taken by surprise may be compared to a sleep- ing man attacked by a well-prepared enemy. Astonishment, confusion, and alarm are opposed to coolness, preparation, and confidence; and severe blows are received before any can ,be given in return. The surprised army must possess many elements of superiority over its assailant to be able to over- l8 SECURITY AND INFORMATION. come the enormous disadvantage at which it is taken ; and a surprise generally means a defeat. If the entire army were constantly on the alert, its sur- prise would be impossible: so, too, if the plans and move- ments of the enemy were accurately known by the com- mander, surprise could easily be avoided. But to keep the entire force continually on the watch would be to ruin it by physical hardship; and a knowledge of the enemy's move- ments and objects is generally incomplete and usually infer- ential. To guard against surprise without making undue demands upon the endurance of the soldiers, use is made of covering detachments, which should be strong enough to hold the enemy while the main body is preparing for action. On the march the security of the army is thus provided for by advance guards, rear guards, and flanking detachments: at a halt a chain of outposts jjrotects it from surprise. Information in regard to the enemy is the indispensable basis of all military plans, and nothing but faulty disposi- tions for the security of an army can be expected if such information is lacking. Moreover, the covering detach- ments, being nearer the enemy than the main body is, are charged either with gaining this information, or with the support of patrols or detachments engaged in scouting and observation. In military science the two elements of secur- ity and information are, therefore, inseparable. The information necessary for a commander is of two kinds: 1. That relating to the geography, topography, and re- sources of the theater of operations. 2. That which relates to the strength and composition Df the enemy's forces, and their position, movements, and morale. Among military nations, the first kind of information INTRODUCTION. I9 is now generally obtained in time of peace, and compiled by a bureau .of military intelligence at the headquarters of the army. This has not, however, always been the case. When the Crimea was selected by the Allies, in 1854, as a thea.ter of operations, it was practically a terra incognita. Hamley says : "It was as completely an unknown country to the chiefs of the allied armies as it had been to Jason and his argonauts when they journeyed thither in search of the Golden Fleece. It was known to contain a great harbor, and a city with docks, fortifications, and arsenal; but the strength and resources of the enemy who would oppose us, the nature of the fortifi- cations, and even the topography, except what the map could imperfectly show, lay much in the region of speculation."* Our own military history offers, if possible, still more striking instances. Such was the lack of information con- cerning Mexico, that our war with that country lasted a year before definite plans of campaign were adopted. Taylor's movement upon Monterey was avowedly for the purpose of obtaining information respecting the capacity of the country to sustain a force of 6,000 men or more; and Wool's expedi- tion against Chihuahua, undertaken upon insufQcient infor- mation, terminated fruitlessly at Moncl.ova, more than three hundred miles from its objective. In the War of Secession much of the theater of war had never been accurately mapped, and in many instances the topography of the immediate theater could be learned only by reconnaissances conducted during the military operations. In his testimony before the Committee on the Conduct of the War, General McClellan said: "Our maps proved entirely inaccurate, and did us more harm than good, for we were con- stantly misled by them." In his report he states: "The *"The Wax in the Crimea," page 24. 20 SECURITY AND INFORMATION. country, though known in its general features, we found to be inaccurately described in essential particulars in the only maps and geographical memoirs or papers to which access could be had. Erroneous courses of streams and roads were frequently given, and no dependence could be placed on the information thus derived. Reconnaissances, frequently under fire, proved the only trustworthy sources of information." Delays and embarrassments were caused by incorrect maps and faulty topographical information in Grant's Virginia campaign also.* Such instances will be more rare in future, and a nation contemplating the invasion of another country will generally possess beforehand an accurate knowledge of its geography, topography, and resources. But in the invasion of any Cen- tral American or South American country, we should, prob- ably, labor under the same disadvantages, in this respect, that were encountered during the War of Secession; and topographical reconnaissance becomes thus a matter of much importance to American officers. This subject belongs, how- ever, to military topography rather than to tactics, and i« exhaustiveh' treated in several well-known works.f The second class of information is gained in two ways: 1. From spies, deserters, prisoners, newspapers, etc. 2. By reconnaissance. The first method does not pertain to the subject of tac- tics. All the information gained in this manner is collated at the headquarters of the army, to which all information in regard to the enemy should be sent without delay.;]; *See Humphreys' "The Virginia Campaign of '64 and '65," pages 128 and 211; also "Personal Memoirs of U. S. Grant," Vol. II., page 243. . tThe student is referred to Root's "Military Topography," and to Chapter VII., Vol. I., and Chapter VIII., Vol. II., of Bronsart von Schellendorf's "The Duties of the General Staff" (Hare's translation). JFm'ther on this subject, see Chapter VII. INTRODUCTION. 21 In the subject of tactics we have, then, to deal solely with military reconnaissance, in contradistinction to topo- graphical reconnaissance. A reconnaissance may be effect- ed by forces varying in size from a single scout to an entire division ; and the reconnoitering force may consist of infant- ry or cavalry, of both, of all three arms, or of cavalry and horse artillery. To gain reliable information of the enemy, contact with him should be quickly gained and never lost. On the march bodies of cavalry, pushed out in advance, come in touch with the advanced parties of the enemy, which they endeavor to drive in or brush aside, at the same time covering their own army with a veil which the enemy must be prevented from penetrating. If the army is at a halt, and the enemy is ad- vancing, similar reconnoitering bodies are pushed out to meet him while he is still at a distance. Reconnaissance is thus primarily performed by a screen of cavalry extended well to the front of the main body. It is also conducted by bodies of troops sent out from the main body or its advanced detachments or posts. The question of reconnaissance is inseparable from each of the subjects con- sidered in the following chapters. SECUMTY AND INFORMATION. CHAPTER II. THE ADVANCE GUARD. Marches in the vicinity of tlie enemy can not be made with too' much precaution and prudence.— i/ariKOHf. Troops moYing in one body would, if they came suddenly upon the enemy, certainly be thrown into confusion, and per- haps defeated, before deplo3'ment for action could be effected. Moreover, insignificant bodies of the enemy could seriously delay the march of the column by causing it to halt and deploy for action. A column of troops on tlie march is, therefore, divided into a main l)ody, an advance guard, a rear guard, and such flanking parties as may be necessary. The objects of the advance guard are, in general terms, to observe and to resist ; specifically, they are : 1. To provide for the security of the main body by giv- ing it time for deployment when the enemy is encountered. 2. To clear the way for the main body and prevent its march from being delayed. 3. To seize and hold important points until the arrival of the main body. 4. To support the reconnoitering cavalry, and afford a rallying point for it in case it is driven in by the enemy. Even when a cavalry screen is operating in front of the ad- vance guard, the latter should not relax its vigilance. The cavalry may be driven in, and the advance guard must then checli the enemy. On advance the security of the column must, therefore, depend essentially upon the advance guard. Strength. — The, proportionate strength of the advance STRE^fGTH OF THE ADVANCE GUARD. 23 guard varies with the size of the main body, the object of the march, the topography of the country, and the nature of the enemy. In a close, rugged country, and' against an enemy inferior in numbers and morale, it should be less than in an open country, against a strong, aggressive enemy, or when tlie intention is to bring on a decisive engagement. With a lar^e force the proportionate strength of the advance guard is larger than in the case of a small column. No abso- lute rule for the strength of the advance guard can be given. If too weak, it can not fullill its proper functions; if too strong, there will be a hurtful waste of energy, for service with the advance guard is much more fatiguing and exhaust- ing than marching with the main column. Moreover, a strong advance guard has a tendency to engage an enemy seriously, even when its duty requires that it should merely fight a delaying action to gain time for the main body. As a general rule (subject, however, to a multitude of exceptions), we may assume the strength of the advance guard to be one-sixth of the whole force, and the rear guard to be half as strong as the advance guard. On a retrograde movement the relative strength of the advance and rear guards would be reversed. The flanking parties are taken from the advance and rear guards, except in the case of very large f orces,when they would be separate bodies of a strength according to circumstances. Thus we have about a fourth of the whole force on duty with the covering detachments on the march. With a small force the advance guard might be reduced to one-eighth, or even one-tenth, of the whole. The time re- quired for the deployment of a large column (such, for in- stance, as an army corps) being much greater than in the case of a small force, the delaying action of the advance guard must be much longer, and its strength much greater. 24 SECURITY AND INFORMATION. In the Franco-German war the German columns sometimes pushed forward half of their force as advance guard, and never less than one-fourth. But this proportion can not be recommended; for no advantage worth considering seems to have been gained by these great advance guards, while they frequeptly brought on battles, as at Spicheren, Worth, and Colombey, contrary to the wishes and plans of the com- manding general. In view of this tendency of large advance guards to commit themselves to serious engagement, Von der Goltz says: "The advance guard must be only small. It was formerly the rule to employ a third or fourth part of all the troops on this duty. The justification of this propor- tion appears very doubtful. The commander-in-chief parts with a considerable portion of his own troops, and creates an independent will beside his own." A large advance guard, by engaging seriously, is likely to defeat the object for which it is created; for instead of gaining time for the main body to deploy, it hurries it into action. Von der Goltz adds: "The experience of the late wars has taught us that the main body never, as a rule, deployed, because the urgently needed assistance required by the advance guard when struggling with a superior enemy demanded that the troops should be led by driblets straight into the battle." It seems, therefore, that, even in the case of large forces, the advance guard should not have so great a proportionate strength as the Ger- mans gave it, and that it should be so composed as to admit of its withdrawal from action, if desirable, without precipi- tating a battle. Formation. — An advance guard consists of a series of detachments increasing progressively in size from front to rear, each being charged with the duty of protecting from surprise the body immediately following it and gaining time for the latter to prepare for action. FLATEZ COMPANY OF INFANTRY AS ADVANCE GUARD. * . * POINT * * S * * FLANKERS *.— ISO YDS-->— 150 VOS -,t* FLANKERS I SECTION '•+'' ADVANCE PARTY * 4 FLANKERS *-., -..* FLANKERS SECTION "■^"support I PLATOON < > * 4 *: * i'i MAIN BODY FORMATION OF THE ADVANCE GUARD. 27 The advance guard is divided into two parts :• the reserve and the vanguard. The reserve consists of from one-third to one-half of the entire advance guard. The remainder con- stitutes the vanguard, which is divided into the advance party and the support, the latter being generally twice as strong as the former. In large advance guards this proportion is often different; the support, relatively to the advance party, and the reserve, relatively to the vanguard, being considerably greater. These proportions are, moreover, varied according to the most convenient subdivisions of the organizations composing the advance guard. They may be regarded as suitable in most cases. The following is given as a typical (but by no means in- variable) formation of a company forming the advance guard of a battalion. {See Plate 1.) The advance party (one section) throws forward a "point'' consisting of three or four men under a non-commis- sioned officer. On each side a flanking group of four men marches about 150 yards from the main route to the right and left rear respectively of the point. Each flanking group should be under a corporal or old soldier, and would habitu- ally march with two men in front and one in rear of the group leader, though the formation adopted would depend upon circumstances.* The rest of the advance party follows 100 yards in rear of the point. The support (one section) follows the advance party at a distance of 200 yards, throwing out two flanking groups of four men each to its right and left front, and somewhaft far- ther out than the flankers of the advance party. These groups can safely move farther out than those of the advance party, thus extending the fleld of view; while each can, if neces- sary, protect by its fire the outer flank of the group in front. . *See chapter on Reconnaissance. 28 SECURITY AND INFORMATION. All Hanking groups should be relieved every hour, if practi- cable, as their duty is much more fatiguing than that of the men marching on the main route. A connecting file, de- tached from the advance party, marches between the ad- vance party and the support to aid in the transmission of in- telligence from one to the other. On many roads bicycles can be advantageously used by the connecting files. The reserve marches about -500 yards in rear of the sup- port, a connecting file marching between them. The reserve may throw flanking groups to the front or to the front and rear, the groups being slightlj' farther out than those of the support. The flankers from the reserve can generally be dispensed with, and should be thrown out only when reason- able prudence requires them; for, as a rule, the reserve should be kept entire and well in hand. The main body follows the reserve at 500 yards, one or two connecting files marching between the two bodies. The distances given above are all variable; but those from the support to the reserve, and from the reserve to the main body, can not prudently be made more than 600 or 800 yards, respectively, in the case of so small a force as the one consid- ered. In the case of a single companjf acting as an advance guard, the rule for the proportionate strength of the advance party and the support is necessarily modified to accord with the most convenient subdivisions of the company. If the nature of the country is such as to render the use of flanking groups impracticable, both the advance party and the support move forward entire, with the exception that the advance party is always preceded by a point. When marching in an open country, the entire advance party may be deployed as skirmishers, with considerable in- tervals, the support following in line of squads. Both lines may be straight or echeloned back slightly from the center PLATE IT. PermisSLble formation of a Company of Infantry as Advance Guard on Open Ground *,♦*♦**»*•**;***•*******•,* \ Advance party deployed /' \ 8 Support in line of Squads (1 Se*:tion} Jieseri/e in. column of fours. Main Body DISTANCE FROM MAIN BODY. 3 1 toward the flanks. The reserve should ordinarily be kept in column. (See Plate II.) When the advance guard consists of a battalion, the first and second companies constitute the vanguard, and the third and fourth the reserve. In this case, the first platoon of the first company constitutes the advance pai'ty, the support consisting of a company' and a half. The distances may be as follows : From point to advance party, 150 yards ; from advance party to support, 200 yards ; from support to reserve, 600 yards ; from reserve to main body, 800 yards. (See Plate ni.) In the case of two battalions acting as the advance guard of a brigade, the vanguard and reserve would each consist of a battalion, the advance party consisting of a com- pany, and the support of three companies. The distances would be about the same as in the case of a single battalion. Distance from Main Body. — The distance from the ad- vance guard fo the main body depends so entirely upon cir- cumstances that it can not be made subject to any rigid rule. If the distance were too great, the advance guard might be forced into a heavy engagement while beyond the assistance of the main body, and might even be entirely cut oif by an attack upon its flank and rear. If, on the other hand, the distance were not great enough, time could not be afforded for the preparation of the main body for action. The advance guard should be far enough ahead to enable the commander of the column to make his plan of action with- out extreme haste while the advance guard is still success- fully resisting the enemy; but it should not be so far in ad- vance that the commander of the main body should be obliged to abandon every other consideration to the one ob- ject of hurrying to. the succor of the advance guard. A rough rule, which will answer in many cases, is that the minimum distance should be equal to the depth of the 32 SECURITY AND INFORMATION. main body; as the time required for the rear troops to deploy on the head of the column would not be greater than that taken by the advance guard in falling back. It is evident that this rule will not answer when a large force is acting with energy and aggressiveness for the pur- pose of bringing on a battle, as the advance guard must then be promptly supported. At Mars-la-Tour, when the German army was moving forward with the object of stopping Ba- zaine's retreat and bringing him to battle, the advance guard of Sttilpnagel's division, being separated by a considerablf distance from the main body, was so roughly handled by the enemy that the leading battalion of the main body had to be hurried into action without deployment, and the escape of the division from disastrous defeat was due only to the fail- ure on the part of the French to take advantage of the oppor- tunity presented. The distance will also depend upon the nature of the country and the state of the weather. If the country is full of defensive positions, such as to admit of a sturdy delaying action on the part of the advance guard, the distance may be decreased. In foggy weather, or at night, or during a storm of rain or snow, the distance should be decreased, as well as the front covered by the scouting groups or flanking parties. If, on the other hand, the country is open, the weather clear, and there is danger of the advance guard being driven back, the distance must be increased. It will be observed that, in the typical formations given above, the main body is from 1,300 to 1,750 yards from the point, while the reserve is from 800 to 950 yards from the point. Even if the enemy were so well concealed, and the advance guard so careless, that the point should be in actual contact with the enemy before opening fire, the reserve would be at least 800 yards from the hostile force. In almost PLATE HI BATTALION AS ADVANCE GUARD. 4-,- ISO VDS->'- 150 YD9-^ I PLATOON ^'advance PARTY. 4 3 PLATOONS ^ SUPPORT 2 COMPANIES RESERVE MAIN BODY COMMANDER OF THK VANGUAKD. 35 every conceivable case, the iirst shots fired by the point or flankers of the advance party would be at such a range that (with the distances given above) the reserve could prepare for action before coming under destructive fire. The reserve is the first body that really demands time for deployment. It is essentially the fighting part of the advance guard ; the vanguard is the reconnoitering part. The Commander of the Vanguard. — The vanguard should always be commanded by an officer, who should be mounted, if possible, and furnished with a detailed map of the region through which the force is marching. He habitually marches with the support, but goes to anj^ part of the vanguard^ where his presence may be necessary. He may take immediate com- mand of the advance party, if it seems advisable to do so, leaving the support under the immediate command of the officer or non-commissioned officer next in rank. If guides are present, they should accompany the support and be under the orders of the commander of the vanguard. It is the duty of the commander of the vanguard: 1. To see that the proper road is taken by the point. 2. When cross-roads are jitissed, to see that a man is left to guide the main column. 3. To send out special patrols to examine all ground that might afford shelter to the enemy, such as woods, farm- houses, hamlets, etc. 4. To send out special patrols to watch and oppose any hostile patrols that may be seen, or whose presence may be suspected. 5. To cause necessary repairs to be made in roads, bridges, approaches to fords, etc. 6. To transmit promptly to the commanding officer of the advance guard all information that he may gain about the enemy, first testing its accuracy as far as possible with- 36 SECURITY AND INFORMATION. out delaying tbe transmission of important news to the commander. 7. To see that the march of the column is not, under any circumstances, unnecessarily delayed. The support replaces any men of the advance party who may be relieved or placed hors da comhat. When a scout of the advance party brings in important inf ormation,he should, if practicable, be sent to the commander of the advance guard. His place with the advance party is at once supplied from the support. He is retained with the reserve, from which another man is sent forward to the support. The num- ber of men with the point and flankers should, if possible, remain unchanged. When there are particular reasons for sending the man back to his former post, the man who re- placed him should be returned. Staff Officer. — In a command of considerable size a staff officer usually accompanies the vanguard, and is charged with the duty of selecting a camp or bivouac for the main body. When he has selected the place, he remains there with such a detail as may be necessary, until the arrival of the main body, the advance guard marching on and forming the outpost, at least temporarily. The Commander of the Advance Guard. — The commander of the advance guard is generally with the reserve; but, on approaching the enemy, should go wherever his presence is most needed. He should always be mounted, if practicable, even in the case of a small advance guard. With the excep- tion, perhaps, of the commander of the rear guard in retreat, no officer needs a more perfect combination of courage, self- reliance, and good judgment. A timid officer in command of an advance guard would suffer the column to be delayed by small parties of the ene- my; a rash one would plunge into combat, and might thus THE COMMANDER OF THE ADVANCE GUARD. 37 impose upon his superior a course of action at total variance with his plans. Small parties of the enemy should always be quickly driven back. On the other hand, an engagement should generally be avoided, unless the commander of the advance guard has orders to touch upon the enemy and bring him to a stand at all hazards. The commander of the advance guard should continually consider the measures necessary for the security of the march, and for rapidly gaining reliable information of the enemy. He should carefullj' observe the ground, and con- sider the tactical use that might be made of it, and should have a clear idea as to what he intends to do in case the enemy is encountered. His orders will be either to march in a certain direction and arrive promptly at a certain point, to pursue the enemy vigorously, or to follow him with prudence, and profit by his faults and by all advtmtages that offer them- selves. In the first two cases he should execute his orders promptly and exactly. In the last case he should move cau- tiously, venturing upon any particular route only after hav- ing well weighed the probable results of his decision. Halts. — Whenever the advance guard halts, all ap- proaches should be reconnoitered and guarded, and an officer should be sent to get an exten ded view from the highest avail- able point. During a short halt each part of the advance guard remains in the place where it is halted. The reserve may usually be allowed to fall out; but the support and the advance party rest or stand at ease, according to the prox- imity of the enemy and the consequent necessity of alertness. If a prolonged halt is contemplated, the advance guard en- deavors first to occupy ground that will furnish a good de- fensive position, behind which the main body is assembled in the best formation for prompt deployment. Signals. — Information from one part of the advance 38 SECURITY AND INFORMATION. guard to another should be conveyed by some code of signals, and shouting and unnecessary firing should be carefully avoided. The point and flankers lire only when they are cer- tain that they have been seen by the enemy and that he is not retiring. Compliments. — Advance guards, as a body, paj' no com- pliments whatever; but individual soldiers on this duty, as on all other, salute when addressing, or addressed by, a superior officer. CAVALRY .\I)VAXCE GUARDS. The formation of a cavalry advance guard is similar to that of one composed of infantry. An advance guard composed of a single troop will be first considered. (See Plate IV.) If the troop consists of but two platoons, the first con- stitutes the vanguard and the second the reserve. If there are three platoons, the first and second compose the van- guard, and the third the reserve. When there are four pla- toons, the first and second form the vanguard, and the third and fourth the reserve. The point consists of four troopers. The flanking groups, eacli consisting of four troopers, march about 100 yards in rear of the point, and from 300 to 500 yards from the line of march. The advance party consists of the point and flankers, and is under the command of a ser- geant, who is generally with the point. In some cases the commander of the advance party may reduce the point to two troopers, holding the other two in rear of the point ahd abreast of the flankers, or he may march in this position him- self without reducing the point. • He should be where he can best command and control the reconnaissance of the advance party. The flanking groups are each commanded by a cor- PLATE m: TROOP OF CAVALRY AS ADVANCE GUARD. i---300 YDS. ^%^ 300 VOS *, * ADVANCE PARTY * 'A MILE .^- ---*- dk '/a MILE RESERVE a MAIN BODY t CAVALRY ADVANCE GUARDS. 4I poral or an old soldier. Generally two troopers ride in front and one in rear of the group commander. The groups may, however, be kept together in any suitable formation, or dis- tributed along the front so as to make an arc of scouts from one extreme flanker, through the point, to the other extreme flanker. The support follows the point at a distance of 500 yards, a flanking group of from four to eight men being sent out on each flank about half a mile from the column and slightly in advance of the reserve. In an enclosed country these groups would march on the nearest roads parallel to the one taken by the main column, and should keep up communica- tion with the advance guard. The reserve follows the support at a distance of 700 yards. As a rule, it is kept entire ; but, if necessary, flanking parties may be thrown out in such a manner and to such dis- tances as circumstances may require. The main body fol- lows the reserve at a distance of 700 to 1,000 yards. Communication between the parts of a cavalry advance guard being much easier than in the case of a corresponding body of infantry, connecting files are not so necessary, and may often be dispensed with. No part of the advance guard should, however, lose sight of the body immediately preced- ing it; and whenever it becomes necessary, one or more troopers should be detached and sent ahead, so as to keep in view both the body in advance and the one from which de- tached. On a winding road and in a rough country connect- ing files are indispensable, but they should be called in as soon as the nature of the terrain renders their services un- necessary. If two troops compose the advance guard, the first troop constitutes the vanguard and the second the reserve. In this case the advance party consists of a half -platoon, if there are 42 SECURITY AND INFORM i.TION. but two platoons in the troop ; or a platoon, if the troop con- tains three or four. The members of the advance party not employed as point and flankers fonn a center group, which marches in rear of the point and abreast of the flankers. Any increase in the strength of the advance party generally in- creases the center group, the point and flanking groups rarely exceeding four men each. In the case of a very large advance guard the advance party should consist of an entire troop, in which case it, in- stead of the support, would furnish the flanking patrols. It will be observed that the distances and intervals are considerably greater in a cavalry advance guard than in one composed of infantry. Cavalry .possessing much greater mobility than infantry, the different covering troops can safely be separated from each other by greater distances in the former than in the latter arm. Moreover, the resisting power of cavalry is less than that of infantty, and when a cav- alry advance guard is driven in by the enemy, the ground is passed over more rapidly in retreat than in the case of a coi*responding infantry force. Hence, in order to give each successive body in rear time to prepare for action, the dis- tances must necessarily be greater for cavalry. It would seem, however, that in our service these distances might safely be reduced; for American cavalry, which can make effective use of dismounted lire-action, has greater res'isting power than European cavalry, and it is not limited, as the latter seems generally to be, to a charge to the front or a flight to the rear. ADVANCE GUARDS OF A1,I< ARMS. 43 ADVANCE GUARDS OF ALL ARMS. To perform its functions thoroughly, an advance guard should be composed of all arms. Reconnoitering duty can be performed more efficiently and more easily by cavalry than by infantry — more efficiently, because a cavalry group can safely push much farther away from the column than an infantry group can, and the field of observation is thus ex- tended; more easily, because a trooper can, with compara- tive ease, reconnoiter to a degree that would exhaust a foot soldier. All European authorities recommend the use of cavalry as reconnoiterers, but prescribe that the support should con- sist in part of infantry to supply the necessary resisting pow- er. In our service this is not in general necessary, as our cavalry has enough resisting power to carry out the delaying action of the support; and nothing but the lack of sufficient cavalry should necessitate the adoption of a composite sup- port. Indeed it is, in most cases, a great mistake so to com- bine cavalry with infantry as to tie the former down to the pace of the latter. The cavalry should ordinarily be given great latitude in pushing forward, for its great object is to gain information; and even when it constitutes the entire vanguard of a composite advance guard, no attempt should be made to fix the distance between the support and the re- serve. If the cavalry push far ahead, the reserve should throw out an advance party with a point and flankers. If pressing closely upon the enemy, the cavalry will probably be delayed enough ty exploration and skirmishing to reduce its progress to the pace of the infantry reserve. Artillery is of great value to the advance guard in pre- paring the way for the infantry attack, and in compelling the enemy to deploy at a distance. Light field batteries only 44 SECURITY AND INFORMATION. should be used with the advance guard, mobility being essen- tial. When the advance guard is specially strong in cavalry, a battery of horse artillery should be attached to it. The guns of a battery attached to the advance guard should be kept together, any subdivision being generally a mistaJke. Under exceptional circumstances, part of the guns may be with the vanguard (marching with the support) ; but in such an advanced position the artillery would be liable to suffer from the enemy's infantry fire at short range, and would be exposed to capture by sudden assault. When the front is restricted and the country is hilly, part of the guns may be with the vanguard ; for the enemy could find advantageous positions from which to bring gnus to bear upon the advance guard, and would have to be opposed by artillery; and in such a country the guns would not be greatly endangered by their forward position, as the enemy could advance only on a narrow front. In a large advance guard (such as that of an army corps) a battery might safely march at the rear of the support. But, as a rule, all the artillery of the advance guard should generally be with the reserve, and should be preceded by a small force of infantry to prevent it from being taken at a disadvantage by sudden attack. In any case, the delay in bringing artillery into action from the\reserve would be so slight that but little would be gained by having guns with the vanguard. As the guns should come into action within, artillery range, but beyond infantry range, of the enemy's position, they would generally be nearer to their proper position if with the reserve than they would be with the support. The battery commander accompanies the com- mander of the advance guard on the march and in reconnais- sance of the enemy, and receives his orders as to bringing the battery into action. A few engineers should march with the support, to re- FORMATION MODIFIED BY TERRAIN. 45 pair bridges, remove obstacles, etc. If the rest of the sup- port consists entirely of cavalry, the engineers' should be mounted. Owing to the small number of engineer soldiers . in our army, this duty would generally be performed by pio- neer detachments from the infantry. The proportion of each arm in the advance guard de- pends upon the nature of the country, the object of the march, and the strength, composition, and proximity of the oppos- ing force. In a close or mountainous country the proportion of infantry should be increased. In an open country the cavalry should be strengthened. If the enemy is strong and near, and a battle seems imminent, the advance guard should be specially strong in infantry and guns. If, however, it is desired merely to develop the enemy without seriously en- gaging, the advance guard should consist of cavalry and light artillery (horse artillery if possible), as these troops can be more readily withdrawn than infantry: In the pursuit of a beaten foe, or whenever the object is to follow and keep touch with the enemy, the proportion of cavalry should be as great as possible. In any case all three arms are needed. As a rule, the different organizations of the command perform in turn the duty of advance guard; but in opera- tions of special importance it may be desirable to have the advance guard composed of select troops. Napoleon says: "It is necessary that the advance guard should consist of lite troops, and that the generals, officers, and soldiers should thoroughly understand their tactics, each according to the needs of his grade. An uninstructed body of troops would be only an embarrassment to the advance guard."* Formation Modified by Terrain. — In the formation of an advance guard considerations of terrain take precedence over all prescribed rules. If, for instance, a ridge from which *"Maximes de Guerre et Pens6es de Napol6on ler." 46 SECURITY AND INFORMATION. a good view can be obtained lies near one of the flanks, the flankers must be pushed out to the ridge, M'hether it be nearer or farther from the flank than the normal distance. When the nature of the country is such that flankers are unneces- sary or can not keep up with the command, dispositions must be made accordingly. Whether on active service or mere- ly at drill, the commander of an advance guard, outpost, or rear guard must exercise judgment, and make his dispositions in accordance ivith the nature of the ground and the real or supposed circumstances of warfare under which he is acting. An ingenious disposition of the advance guard made by General Cox, in West Virginia, in 1861, is worthy of remark. The main body of the command, embarked on steamers, moved up the Kanawha river, on either side of which the enemy might be expected. An advance guard accordingly marched along each bank, the main body being held in readi- ness to land and reinforce whichever one should encounter the enemy. Encountering the Enemy. — As soon as the enemy is seen, the advance guard must endeavor to ascertain promptly whether it has to deal with an outpost of a stationary force, an advance guard of a marching body, or a flanking detach- ment of a column. It should lose no time in discovering where the enemy's main position is, or how far away is the marching column. The relative numbers and position and the orders under which the advance guard is acting will de- cide the (juestion of attacking or taking up a defensive posi- tion. The offensive is generally the best, if an attack seems at all likely to succeed. If between the advance guard and the enemy there is an exceptionally good position, the enemy should be attacked vigorously, in order that the position may be occupied and held for the deployment of the main body. If the defensive has been decided upon, and a good BNCOUNTERING THE ENEMY. 47 defensive position has been passed a short time before the enemy is encountered, or if the latter is in such force that the advance guard can not hold its own against him, it will be necessary to fall back slowly and stubbornly to the posi- tion or upon the main, body ; the commander of the advance guard sending to the commander of the' main body prompt warning of the threatened or actual attack. It is not always necessary for the advance guard to take up a position on the road by which the main body is advanc- ing. If the latter is compelled in its advance to adhere to the route, it is often better for the advance guard to make a stand at one side, holding the road' with only some de- tached troops. The main body advancing along the road is thus sometimes enabled to make its attack in the most effect- ive direction. Moreover, in case the advance guard is driv- en back, it will not be pushed directly upon the main body, to which it might communicate its disorder. In case of a sudden encounter with the enemy, the advance guard will probably be compelled to take up a position as best it may, which will probably be on the road. In this case the main body may sometimes be able to advance by a lateral road, to avoid the danger of being compromised in a reverse of the advance guard, and at the same time gain the advantage of a flank attack upon the enemy. When the advance guard is strong and able to hold its own against the enemy for some time, and when the main body does not follow the advance guard too closely, such a movement may be decisive. 48 SECURITY AND INFORM VTION. ADVANCE GUARD OF A DIVISION. A division consists of three brigades of infantry and two or more batteries of artillery. As no divisional cavalry is provided, a portion of the corps cavalry must be detached and assigned to the division whenever the latter is acting independently, or when the front is not covered by a general screen of cavalry. The corps cavalry will not comprise more than two regiments, and may consist of only one.* It can not, therefore, be safely assumed that more than one squadron will be assigned to each division. The experi- ence of recent wars would seem to indicate four as the proper number of batteries; and it may be assumed, then, that the division consists of three brigades (composed of nine regi- ments, or twenty-seven battalions) of infantry, four baj:teries of light artillery, four troops of cavalry, one company of engineers, three companies of hospital troops,t and a section of signal soldiers. The advance guard of the division might be formed as follows (see Plate V) : The advance party consists of one troop of cavalry, its point being about a quarter of a mile in advance, and the flankers at the same distance from the line of march. A flanking patrol would march on each flank, abreast of the advance party, and from two to four miles from it. Each of these flanking patrols should be not less than a platoon, and should be commanded by a lieutenant or an experienced sergeant. The support follows one mile in rear of the advance party. It consists of two and one-half troops of cavalry, two battalions of infantry, one section of engineers, with a tool ♦Infantry Drill Regulations, pai-agraplis 479 and 484. tNamely, a bearer company, an ambulance company, and a field hospital. Most of the ambuljinces and the field hospital would be with the train. For the details of the organization of a division, see "Organ- ization and Tactics," iiage 34. Orde r of ^March of a Division acting inde/ieri P . -IMiU * ^ s I- »: ^ I tS^S :| k 1 1fl'a||||||||ia--«** .■/4Mile.i -H.'tJ I ■,-o '•>* Ihtse flanking detachments are always alightljj farther out from the line of march than those sent out fiwn the advance /tartif. f I s^ -a-H c s i ^ I 1 V ^ ■H I H ■#■**-♦«•♦■♦ &- .11 Miles. Comnosition of the Division . 3th Infantry 20 th Infantry 13tklnfantry 1st Brigade . eth Infantry \ 1 8th Infantry \ 2nd Brigade . 15th Infantry ) 2Ut Infantry \ 4th Infantry \ ird Brigade . 14thlnfantri/ ] Light Batteru 'J}' 5th Arfy ID'SthArt-y) 'y ■ ■ SVivls 'A' 2nd . I ■ ional Artillmy Co 'A' Battalion of Enyinters 2 Com/tanies of HosfiUal Corps i Section Signal Cor/ts. 2 -Machine Guns manned by details from the Divisional Artillery. i Sijuaclron . ist Cavetlry, attached to Division. i ^ ^ 1- ^ i < "^ 1 ,S r >< ^ R^ 4~ 1 s .?! -^ •5 1 ^ ^ T H ^ i 1 •3 1 1^ u^\ "5 s s •o 1^ I JVote :- The distances jfiven are variable 7h^ organizations rwresented a fuU war strength. 7%e number of fflatoons in e assumed to h^ four. ■ The /tanking patrols ahrytast are taken /H>m the same. There is no attem/tt to indict <^ ammunition carts, as no s^ been adopted bu the It.S, Jn the rear ^uarxi two hattah are in ordinaru column cf rvutt constituting tne rear ^drd for considerable danger" the entire the rear ^uard would be in re^ formation. The rear point and ^anAer- thrown out Ay the rear ^ua cirvurnstances. In considering the distance ^ the rear ^*4.€i.r^f note that tht cons ists of 1^6 wagorts. PI. ATE V. .13 Miles. f the Division . Orde r of tMarch of a Division actin g independent ly/. - ^ .e 4- I I S I s I f S 5\ 55 ^ 1^ 1^ 4^ I #4|*9 •-»'^»-»-»- •-■-■-•' 1 * -!;^ 1 1^ ■^ 1 ^ •^ ■ <4<^4Binq«44^^4-»^-»^^* I Mile o«fl««i4-:-t3-a-ac«» ^ J Mile ^^;44.. II f ^«> \])ivisional ArUllor ij by deCails from thw ttach^et to Division: JVote :- 77ie distances ^iven ctre variable. Ih^ organisations r^uvsented art all assumed U be at full war strength. 7%e number of fflatoons in each caualrif troop is assumed to bv four. • The flanking patrols abreast of the advance partu are taken pom the same. There is no attempt to indicate the exact number of ammunition carts, as no special cart ho^ yet been adopt&d bt/ the U.S. Jn the rear gu^arcC two battalions if the regiment are in ordinartf column