The service of security and information

Front matter

Chap....

UNITED STATES

.... Copyright No..

Preface To The Third Edition

The gratifying reception accorded to the first and second editions of "The Service of Security and Information" encourages the author to hope that the revised edition of the book now presented may not be unwelcome to the officers of the Regular Army and the National Guard.

Profiting by the kind criticism of his brother officers, and by his own experience in using the work 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 changes are neither 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. Mills, 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.

U. S. Infantry and Cavalry School,

Fort Leavenworth, Kansas,

February 1, 1896.

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 American text-book 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 characteristics, 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 our 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 discovered, 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 our own military history, and to apply to them the touchstone of American practice in war. To this end he has submitted his manuscript to several officers of high rank and distinguished ability, who have criticised it in the light of their own extensive military study and great experience in actual warfare.

The author is at a loss for an adequate expression of thanks to Brigadier-General 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 obligations to Lieut-Col. H. S. Hawkins, 23d Infantry, Lieut.-Col. Guy V. Henry, 7th Cavalry, Major H. C. Hasbrouck, 4th Artillery, Major C. C. C. Carr, 8th Cavalry, and Major J. B. Babcock, A. A. G., for valuable information and comments. To Lieut.-Col. Henry, Captain E. S. Godfrey, 7th Cavalry, and First Lieutenant Thomas Cruse, Gth Cavalry, the author is indebted for most of the information on which the chapter on "Indian Scouting" is based. To Colonel E. 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.

panied 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 appearance 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 carried. 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 oculis*t. 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 render 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.

LIST 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 Legere, De Brack. Battles and Leaders of the Civil War.

Campaigns of Stuart's Cavalry, H. B. McClellan. Catechism of Military Training, Marryatt. Cavalry Field Duty, Von Mirus (tr. by Russell). Cavalry 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-BelD.

PREFACE. 9

Duties of the General Staff, Bronsart von Schellendorf.

Elements of Modern Tactics, Shaw.

Extracts from an Infantry Captain's Journal, Von Arnim (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, Rustow (tr. by Savin de Larclause). Letters on Cavalry, Prince Kraft zu Hohenlohe Ingelfingen. Life of Andrew Jackson, Parton.

Methodes de Guerre Actuelles, Pierron.

Minor Tactics, Clery.

Maximes de Guerre, Napoleon.

Memoirs of U. S. Grant.

Memoirs of W. T. Sherman.

Napoleon's Expedition to Russia, Segur. Official Records of the War of the Rebellion. Operations of War, Hamley.

Precis of Modern Tactics, Home.

Reglement sur le Service des Armees en Campagne, De Savoye. Service d'Exploration et de Surete, Bonie. Soldiers' Pocket Book, Wolseley.

Studies in Troop Leading, Verdy du Vernois. Tactical Deductions from the War of 1870-71, Boguslawski. Tactique de Perizonius.

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.

IO CONTENTS.

Contents

PRELIMINARY DEFINITIONS Page 14

Introduction

The punctilio of private combat not applicable to the operations of war.— Condition of an army taken by surprise.— Security and information inseparably connected. — Information necessary for a commander.— How obtained.— Exceptions in former wars.— Kind of information 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. — Signals.— Compliments.— Cavalry advance guard.— Its formation.— Advance guard of all arms.— Formation modified by terrain.— Encountering 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 neglect of outpost duty.— Duties of outposts.— Subdivisions of the outposts.— Two systems of outposts.— Position.— Strength.— Composition.— 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. — Supports. — Cossack posts. — The reserve. — The outpost at night. — Outpost patrols. — Visiting patrols. — Reconnoitering patrols. — Strong patrols. — Posting the outpost. — Defense of the outpost.— Relieving the outpost Page 56

Chapter IV

Importance of reconnaissance.— Kinds of reconnaissance.— Reconnaissance in force.— How conducted.— Objections. — Historical instances.— Special reconnaissance.— Historical instances.— Patrolling.

CONTENTS. 1 1

—Exploring patrols.— Small infantry patrols.— Composition.— Preparation and inspection.— Signals.— Formation of the patrol.— Conduct of the patrol.— Encountering the enemy.— Inhabitants.— Guides. —Reconnaissance of different kinds of ground.— Cross-roads- Heights.— Denies.— Bridges or fords.— Woods.— Inclosures.— Houses.— Villages.— Cities and towns.— Reconnaissance of s the enemy in position.— Reconnaissance of the enemy on the march.— Signs and trails.— Reports.— Strong infantry patrols— Expeditionary patrols- Prisoners.— Harassing patrols.— Flank patrols.— The advance guard passing through a town.— Cavalry patrols.— Historical instances- Connecting patrols.— Pursuing patrols.— Cyclist patrols.— Balloon reconnaissance Page 107

Chapter V. The Cavalry Screen

Screening and reconnoitering duty in the Napoleonic wars.— Revival of the duty in the War of Secession.— The cavalry screen in recent European wars. — By whom the duty may be performed. — Distance of the screen from the army. — Frontage of the screen. — Formation 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.— Officers' patrols. —German patrols after Spicheren.— Battle of Tom's Brook.— Separation of the duties of security and information.— Transmission of intelligence.^Contact and fighting.— Buford at Gettysburg— Protecting 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 pursuits not often made.— Duty of the rear guard.— Ney's method.— Strength of the rear guard.— Morale.— Offensive 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.— Communication between the several parts of the rear guard and with the main body. — Protection of the flanks. — Riistow's intermediate body. — Contact 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 country— The rear guard in a forward march.

12 CONTENTS.

Chapter VII. Spies

Military and civilian spies.— When the services of spies are most valuable.— Persons who should be selected as spies.— Qualities requisite in a spy. — Compulsory espionage. — Double spies. — Concealment of messages. — Spies as a check upon each 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 detection of spies. — Their search. — The management of the secret service.

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 publication Page 233

Chapter VIII. 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. —Skill in selection of positions 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 topography- Observations Page 242

APPENDIX I.

Advance guard drill (Infantry).— Advance guard drill (Cavalry).

APPENDIX II.

Questions for General Review Page 257

INDEX Page 283

ILLUSTRATIVE PLATES. 1 3

ILLUSTRATIVE PLATES.

Outpost Line, Showing Changes Made at Night. .Frontispiece.

Facing Page.

I. Company of Infantry as Advance Guard 27

II. Permissible Formation of a Company of Infantry as Advance Guard on an Open Plain 31

III. Battalion as Advance Guard 32

IV. Troop of Cavalry as Advance Guard 38

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 VIII. Comparison of Cossack Posts with the Picket System .... 86

IX. Patrol 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 206

XV. Troop of Cavalry as Rear Guard 208

14 PRELIMINARY DEFINITIONS.

PRELIMINARY DEFINITIONS.

Abatis— 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 operations is most generally that of supply— though not necessarily so, at least as far as food is concerned." — Jomini.

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.

Communications— -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 holding 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 individual 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 — Baggage, 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. * 1 5

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 commanding 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 campfollowers; to take charge of stragglers, prisoners, and deserters; and to superintend the secret service.

Shrapnel— Called the "man-killing projectile." A shell filled with bullets, and having a bursting charge only sufficient to break the case 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 art of handling troops on the field of battle.

Terrain — The topography of a field, considered especially in its relation to tactical operations.

Theater of War— "The theater of war comprises all 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 axmy."— J omini.

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."— Ibid.

Yedette — A mounted sentinel.

Chapter I. Introduction

It is pardonable to be defeated, but never to be taken by surprise.— Frederick the Great.

If opposing armies could march unmolested to a designated 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 individuals 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 niay be compared to a sleeping 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 overcome 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 surprise would be impossible: so, too, if the plans and movements of the enemy were accurately known by the commander, 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 movements and objects is generally incomplete and usually inferential. 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 protects it from surprise.

Information in regard to the enemy is the indispensable basis of all military plans, and nothing but faulty dispositions for the security of an army can be expected if such information is lacking. Moreover, the covering detachments, 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 security and information are, therefore, inseparable.

The information necessary for a commander is of two kinds:

1. That relating to the geography, topography, and resources of the theater of operations.

2. That which relates to the strength and composition of the enemy's forces, and their position, movements, and morale.

Among military nations, the first kind of information

INTRODUCTION. 19

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 theater of operations, it was practically a terra incognita. Haniley 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 fortifications, 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 concerning 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 expedition against Chihuahua, undertaken upon insufficient information, terminated fruitlessly at Monclova, 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 W T ar, General McClellan said: "Our maps proved entirely inaccurate, and did us more harm than good, for we were constantly misled by them/' In his report he states: "The *"The War in the Crimea," page 24.

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. Bat in the invasion of any Central American or South American country, we should, probably, 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, however, to military topography rather than to tactics, and is exhaustively 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 tactics. 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 4

*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).

^Further 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 topographical reconnaissance. A reconnaissance may be effected by forces varying in size from a single scout to an entire division ; and the reconnoitering force may consist of infantry 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 ariny with a veil which the enemy must be prevented from penetrating. If the army is at a halt, and the enemy is advancing, 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 considered in the following chapters.

Chapter II. The Advance Guard

Marches in the vicinity of the enemy can not be made with too much precaution and prudence. — Marmont.

Troops moving in one body would, if they came suddenly upon the enemy, certainly be thrown into confusion, and perhaps defeated, before deployment 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 the march is, therefore, divided into a main body, 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 giving 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 advance guard, the latter should not relax its vigilance. The cavalry may be driven in, and the advance guard must then check the enemy. On advance the security of the column must, therefore, depend essentially upon the advance guard.

Strength. — The, proportionate strength of the advance

STRENGTH 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 eneiny. 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 the intention is to bring on a decisive engagement. With a large force the proportionate strength of the advance guard is larger than in the case of a small column. No absolute rule for the strength of the advance guard can be given. If too weak, it can not fulfill 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 exhausting 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 required for the deployment of a large column (such, for instance, 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.

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 frequently brought on battles, as at Spicheren, Worth, and Colombey, contrary to the wishes and plans of the commanding 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 proportion 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: u 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 Germans gave it, and that it should be so composed as to admit of its withdrawal from action, if desirable, without precipitating a battle.