Fortification Friday: “a redan or a lunette, is thrown up on the exterior to cover the outlet”

Before we close the discussion of openings for forts (see what I did there?), let me circle back to compare Mahan and Wheeler in regard to one of the fine points considered.  That being the use of a detached redan or lunette in advance of the outlet.  Recall that in pre-war writing, Mahan suggested:

In very frequented passages, a redan or a lunette, is thrown up on the exterior to cover the outlet, and thus ensure its safety in case of surprise.

And Wheeler, in the post-war, mentioned a similar arrangement, but perhaps narrowed the application to those larger outlets, for sorties, where simple interior traverses would not be practical.

Mahan offered two figures that illustrated the redan to the front of an outlet:

PlateVIIFig48_49

Figure 48 offers a wide redan in front of an outlet, which is further covered and flanked by by the “horns” of the larger work.  A very well protected outlet, we might say.  Mahan considered this a Redan Line.

On Figure 49, we see much more complexity.  Particularly with the defensive lines of fire.  The outlet is nested within a redan of a larger line.  On both sides are faces within redans of differing angles. This is considered a Tenaille Line – a proper definition we will discuss later.  But the point being the covering redan, to the front of the outlet, was absolutely necessary here in order to protect that weak spot.  The covering redan is somewhat off center of the outlet, perhaps to limit exposure at the expense of accessibility.

Wheeler, as you may recall, gave us only a simple rendition of the covering redan:

WheelerFig51

The question I have in regard to these advanced, detached “parts” covering openings is… just how often were these employed during the Civil War?

When examining surviving earthworks, we often find the area around the outlets obliterated.  Sometimes, due to necessity, that is done to facilitate visitor access.  But more often, just a case where the structures around the outlets were the most susceptible to erosion.

And when examining wartime plans, we see some use of these redans… but more often not.  Consider Fortress Rosecrans outside Murfreesboro:

FortressRosecrans

This was, some have said, the largest fort built during the war.  And in this plan we see examples of many features suggested by Mahan.  Specific to the outlets, we see up near the top that Battery Cruft was a detached lunette (maybe a “half lunette”) covering an outlet.  Elsewhere, such as next to Lunette McCook at the bottom right, we see an outlet (an existing road) without a covering redan or traverse.  Though we do see obstacles erected to the right of Lunette McCook.  And certainly that named work was positioned to dominate the approaches to the outlet.  Furthermore, what you don’t see in my “snip” are works in advance of the fortress that covered the railroad and road.  Though those were oriented south and not regarded as covering the outlet in question.

Another plan to consider is from Virginia, at Deep Bottom:

DeepBottomSnip

Here we see five road crossings at the main line of the works.  One of those is blocked entirely by a redan.  The other four (including one that appears to be a path cut just to clear a redan) have no traverses or covering works.  Just obstacles placed in front.

If we are assessing the protection of outlets, with Mahan’s suggestions in mind, we find a mixed application of those covering redans.  Seems to me the use of that sort of feature was based on the engineering assessment of need.

Now considering such use under Wheeler’s suggested implementation, let’s look to the location of a few large scale sorties.  First, how about the works were the Crater assault was mounted:

CraterSector

And further around the lines, and further forward in the historical timeline, to the sector around Fort Mahone:

FortMahoneSector

And to the left of that sector near where the Federal Sixth Corps mounted their sortie:

FortWelchSector

Now the scale of these maps mean these are not so much “plans” as operational maps.  So we know there are structures that escaped the pen here.  But what stands out, with double underlines, is the use of something far more elaborate than Mahan and Wheeler discussed.  We see entire sections of works advanced in a manner to provide staging grounds for those formations preparing for the assaults. Major assaults, mind you, involving whole divisions.  These were, you see, works built for the offensive.  Grand offensives!  In that light, might we say the entire Federal line was one large “covering work” in front of an array of staging areas and supply depots?

Fortification Friday: Barriers, Bridges, and Ramps … the fort “communications” infrastructure

Writing the instructions for cadets, almost two decades after the Civil War, Junius B. Wheeler focused more on the functional requirements of outlets in the fortifications, as opposed to the important details of construction.  The nuances here are, I think, important.  Mahan presented the outlet had important operational uses within fortifications, but proceeded to discuss the particulars assuming the student would understand what those uses were. Wheeler focused on the uses up front, citing communications as the need and outlets as the remedy. And we must broaden “communications” a bit, perhaps our 21st century writers might say “traffic” and refer to movement of personnel, supplies, as well as messengers carrying communication.

Wheeler added to Mahan’s instructions with mention of “turn back” traverses at the mouth of outlets (to reduce the area under enemy lines of fire) and wider outlets for sorties.  But for the most part, the construction techniques remained the same.  Likewise, Wheeler identified the same supplemental structures as Mahan – barriers and bridges – while adding a few embellishments.

First off, we have the barriers. Which were… well… gates:

Barriers. – The outlets are usually arranged so that they can be quickly closed, to guard against surprise. The means used is a gate, technically termed a barrier.

The gate is made with two leaves, hanging on posts by hinges, and made to open inward.

The frame of each leaf is composed of two uprights, called stiles; two cross pieces, one at the other at the bottom, called rails; and a diagonal brace, called a swinging bar.

The leaf of the barrier may be open, by spiking stout upright pieces, with intervals between them, to the pieces of the frame; or it may be made solid, forming what is known as a bullet-proof gate.

Yes, something you might purchase, pre-fabricated, at the home improvement store.  But note that Wheeler offered two versions – a light “open” leaf version with spaces between the uprights AND a heavy “bullet-proof” version with no spaces.  The latter was illustrated in Figure 52 of Wheeler’s book:

WheelerFig52

Wheeler added some practical observations about the construction of these heavy gates:

Since the gate must be strong, the leaves of it are necessarily very heavy.  The leaves must be hung upon stout posts, firmly braced into the ground, to sustain the great weight of the gate.

The top rails of all barriers should not be less than six feet above the ground.

In the barriers with open leaves, the vertical pieces are usually extended from eighteen inches to two feet above the top rails, and their upper ends sharpened.

In those which are solid, it is usual to arrange some obstruction upon the top rail, such as sharp pointed spikes, broken glass, etc., to interfere with persons climbing over the top. It is usual to provide apertures in the leaves, through which the men can fire upon the ground outside.

Gotta love those details.  From having a “peephole” to shoot out from to having broken glass atop the gate.

Bridges were another supplement to the outlet’s composition:

Bridges. – When the ditch has been completed along that part of the work in front of the outlet, it is usual to carry the roadway across the ditch by means of a bridge.

The ditches of field works are, as a rule, quite narrow, and the bridges used to span them are very simple constructions.

A common method of building the bridge is to lay three or more sleepers across the ditch, and cover them with planks laid transversely.  If the span is sufficient to require intermediate supports, these are obtained by using trestles placed in the ditch.

A bridge built in this way can be quickly removed and speedily re-built, if there be any necessity for it.

We might consider this a temporary bridge without any means for retracting or removing, save dismantling.  Thus it was kept to the bare minimum arrangements.

Wheeler mentioned that other “hand-books on military engineering” described the use of draw bridges or rolling bridges in fortifications. He only briefly discussed the former, being basically as that detailed by Mahan in earlier texts.  The latter were designed to be “… pushed out from the work, and drawn back into it.” Both sort of bridges were,

… known as movable bridges, are useful to guard against surprise, to prevent stragglers from entering, and to keep the garrison in the work.  As a defense against an assault of a field work, they are of but little value.

To belabor that point:

The best method, is to have no ditch in front of an outlet, but let the roadway be on the natural surface of the ground.

Of course, operational needs might vary. But you get the point.

Wheeler offered one more supplemental structure under his heading of communications, but not one that was directly associated with outlets.  This was the ramp.  While all writers on fortifications discussed ramps in some regard, Wheeler saw fit to highlight the structure and its role for interior communications (and again, broaden that definition as mentioned above):

Ramps. – The short roads used in fortifications to ascend from one level to another, are termed ramps.

The width of a ramp depends upon its use, following the rule laid down for the width of passages.  A width of six feet for infantry, and of ten feet for artillery, are the widths generally used.

The inclination of the ramp may be as great as one on six, and as little as one on fifteen, depending upon the difference of level between the top and bottom. The side slopes of earth with its natural slope.

The ramps in a work should be placed in positions where they will not be in the way, nor occupy room which may be required for other purposes.

Steps or stairways are sometimes used instead of ramps. The rule for them is that the breadth of each step, called the tread, shall be at least twelve inches, and the height of the step, known as the rise, shall be about eight inches.

They are substituted for ramps in those places where there is not sufficient room for the ramp.

Nothing new or advanced here.  Ramps and stairs were part of fortifications dating back to the earliest times.  What is noteworthy here is that Wheeler considered them part of the fort’s communication infrastructure… again communication in the sense of how one moves into, out of, and inside of the fort.

(Citations from Junius B. Wheeler, The Elements of Field Fortifications, New York: D. Van Nostrand, 1882, pages 151-5.)

 

Fortification Friday: Outlets evolved in the post-war instructions

Earlier we considered the pre-war instructions offered by Mahan in regard to outlets, particularly how those would be constructed.  Training cadets before the war, Mahan covered the topic with a few paragraphs.  Later, after the war, he added a section about bridges associated with the outlets.  However, by the 1880s, Junius Wheeler’s instructions to cadets would sprawl over the better part of seven pages.  Maybe this is simply a case where pre-war there was a premium on copy space for printed manuals.  On the other hand, maybe Wheeler felt “his” cadets needed “special help” getting this particular aspect of fort-building in order.  Or perhaps, which I tend to think, wartime experiences prompted the extended emphasis.

The first thing we see with Wheeler’s treatment of the subject is a focus shift.  Before discussing the construction of these outlets, he steps back to discuss what these are used for.  Notably, the section is titled “Communications, barriers, etc.”:

Communications. – The defenders of a closed work must have arrangements made by means of which they can enter or go out of the work when necessary. In the case of continued lines, arrangements should be provided by means of which the defenders can make sorties.

Word choice here.  Mahan’s writing pressed that outlets were important for servicing the works.  Left unstated, implied at best, were other uses for the outlets – communications, logistics, reconnaissance, or simply just getting out to stretch the garrison’s legs. On the other hand, by selecting this sub-heading, Wheeler set different functional requirements… although, much vaguer than Mahan’s.

Wheeler’s second paragraph discussed the basics.  The outlets had to be made through the parapet, and that created a weak point in the work.  To minimize the risk, he insisted the number of outlets be kept to a minimum and built where least exposed.  Specifically, he gave these suggested placements:

In redoubts, the outlets are on the sides least exposed to attack; in half-enclosed works, they are placed near the middle of the gorge; in forts, they are usually placed near the re-entrants.

And that matches well to Mahan’s suggestions from decades before.  But where we see variations is with the size of these outlets, which Wheeler relates based on functional requirements:

A passage for the use of infantry only should not, as a general thing, be less than six feet wide; for artillery, not less than ten feet wide; for sorties, the outlets in continued lines should be at least fifty yards wide.

See what happened here?  Wheeler took Mahan’s two size categories and then added a third, based on an additional use-case.  I think at this passage Wheeler is thinking back to works at Vicksburg or Petersburg or around Atlanta.  And in those campaigns, field works had become part of an offensive operation – be that a very deliberate siege at some levels, but more dynamic than an “According to Vauban” siege.  Again, not to say wide passages for sorties did not exist prior to 1861, but rather to say those took on different emphasis around about 1863-4… at least in the American context.

Demonstrating that the more things change, the more they tend to stay the same, Wheeler offered this diagram for an idea outlet through the parapet with masking traverse:

WheelerFig50

Yes, he ripped off Mahan.  But give him a little credit for adding more notations and giving us that nice profile on the right.  And he offered the lines (c and g, the “crossing” arrows through the middle) which were the enemy’s “extreme lines of fire”.  Those lines, Wheeler instructed, governed the length of the traverse (T).  Note how those lines are drawn off the corner of the superior slope of the parapet.

Toward that, Wheeler did add a lot more to the notion of masking the outlet:

The length of the traverse may be shortened by turning back the interior crest at right angles to its general direction, and extending it as far as the crest of the Banquette.

This “turn back” is indicated by “B” on the figure.  One on each side of the outlet.  Notice how that would send the lines of fire (again, lines c and g) into a tighter intersection, further back in the outlet, and thus reducing the area the enemy might fire upon. Such angles reduced, the traverse need not be so long.  All in all a nice functional flourish to the outlet design.

Beyond that, Wheeler offered other options that would reduce the vulnerability:

Instead of having a road along its entire front, the traverse is sometimes joined to the parapet on one side of the opening, as shown by the dotted lines b d and e f, in Fig. 50.

And such would mean only one “extreme line of fire” need be considered in regard to traverse length.  But that did mean traffic had a nasty chicane to deal with.

This is all good, but how about that fifty-yard wide outlet for sorties?

The method adopted to mask the interior of the work in this latter case, is to place the traverse opposite the outlet on the outside, and beyond the ditch….

The traverse in this case is usually broken, generally a redan in trace, with the profile of a parapet, but commanded by the parapet in rear.

Figure 51 illustrated this manner of masking:

WheelerFig51

Basically, if you have to provide a wide gap in the works, the only viable solution is to build a miniature work in front to cover it.  Keep in mind, such sortie outlets would be placed on less exposed sections of the line.  And of course, these would be covered by strong faces on either side.  Such would reduce the chance the enemy might target the outlet for their own “sortie”.  And the redan covering the front would further reduce the danger of direct artillery fire.  Note, however, you don’t see a traverse in the interior of the works to cover the sortie outlet.  The purpose of this outlet is to allow infantry in wide columns to emerge in quick order. Bad enough, though necessary, to have that redan in the way.  Putting a traverse on the inside would impose yet another choke point for maneuver… and yet another delay in an operation where time was critical.

Before leaving Wheeler’s discussion of outlets, we’ll also examine the evolution of barriers and bridges.  Furthermore, Wheeler introduced the notion of ramps within these outlets.  All interesting facets to consider with respect to the art of military fortifications.

(Citations from Junius B. Wheeler, The Elements of Field Fortifications, New York: D. Van Nostrand, 1882, pages 148-51.)

Fortification Friday: Drawbridges? For field fortifications?

Last week we looked at the use of outlets in the field fortifications.  Certainly it was impractical to insist the garrison stockpile sufficient food and supplies for the anticipated duration of the conflict at hand… not to mention cross their legs the whole time.  Some sort of gate or entrance was required.  However, that presented a weak point that an attacker might exploit.  Thus Mahan urged his students to build additional structures, namely traverses, to cover those entrances.  That reduced the risk to a degree.

But where the point where the outlet crossed the ditch (if it had to cross a ditch, that is) presented a greater problem.  As we’ve seen in detail, one of the important properties of the ditch was serving as an obstacle to any attack.  But the outlet would require a six to ten foot wide path across the ditch.  Thus granting an attacker a potential highway across.  Common sense response to that problem was to simply build some sort of retractable bridge.  But pre-war, Mahan did not offer that as a direct solution (indeed, avoiding mention of the problem altogether).  But in his post-war edition, Mahan offered:

Draw-Bridge. For the usually narrow ditches of field works, either a light rolling bridge may be used for a communication, from the outlet, across the ditch; or else an ordinary wooden draw-bridge.  A very simple one, and of easy construction, was proposed by Colonel Bergère of the French engineers.

I believe this refers to Colonel Pierre Bergère (1785-1868), but I don’t know of a specific work to reference in regard to the bridges in question here.  I find it interesting the more detailed discussion of bridges enters Mahan’s post-war edition with Bergère serving as a reference and introduction.  Either as if the 1861-65 experience simply followed that of the French engineer, or could not be applied directly.  I have my thoughts, but let’s save that for later.

Mahan offered Figure 45, bis to illustrate the proposed bridge:

MahanFig45bis

Technical details followed:

The bridge is a light platform a,a’, of joists and boards, long enough to span the ditch D, and so arranged as to turn around an axle at A, the crest of the scarp.  At the point B, on each side of the platform, an iron gudgeon is firmly attached to it and turns in the eye of a socket at the end of lever C B.  This lever is formed of two pieces of scantling of some tough flexible wood, each about four inches square. The lever has an eye, at the middle point O, which receives a strong iron bolt that connects two ordinary gun carriage wheels.  The two pieces which form the lever are firmly fastened together, as shown in the figure; a weight, consisting of shells filled with sand, or shot, being fastened at the end c, and serving as a counterpoise to the bridge.  Two rails A, of heavy scantling are laid for the wheels to run upon in maneuvering the bridge; which is done simply by one or two men taking hold of the spokes of the wheels, and so, by turning them, causing them to run backwards or forwards, and thus raise or lower the bridge.

The arrangement is a clean piece of engineering.  But nothing novel or particularly advanced, technically speaking.  Noteworthy is the re-purposing of common equipment, such as carriage wheels and projectiles, on hand with the field army.

But I have to throw a flag out here.  If those building the fortification had ample time to build fancy drawbridges, they were more so working as garrison troops and probably not actively campaigning.  The premise behind field fortifications was those would be temporary structures established as part of a field army’s operations.  Not structures to be garrisoned, which should shade more to the permanent fortifications with far more elaborate arrangements all around.  But experience in the Civil War took the American officers away from some pre-war assumptions about how fortifications would be use.  And more importantly how to classify them.  We’ve already noted that Junius Wheeler began classifying semi-permanent and temporary garrison fortifications within the discussion of field fortifications.

Now this is not to say no self-respecting American engineer in 1861 would consider the drawbridge when planning the outlet to a fort. Rather that in 1861, the use of drawbridges were not emphasized in the classroom.  But by 1870, that changed to provide a couple of paragraphs and a nice illustration based on a French officer’s recommendations.  As we will see by looking at Wheeler’s text, by the next decade, those instructions evolved even further.  Pages, mind you, dedicated to the discussion of small bridges!

(Citation from Mahan, An Elementary Course of Military Engineering: Part 1: Field Fortifications, Military Mining, and Siege Operations, New York: John Wiley & Son, 1870, page 57-8.)

Fortification Friday: Don’t for get the door! Gotta get in and out of the fort

So you’ve built a strong fortification in accordance with Mahan’s instructions.  The fortification has wonderful fields of fire, properly sized parapets, protected batteries, and bombproofs for everything to include the commander’s liquor stash.  Great!

But sooner or later the fort’s garrison has to wonder outside the works.  Say for maintenance of the works, or patrolling the outskirts, or simply for resupply.  So there needs to be a passage to the exterior somewhere in the plan.  Mahan called these outlets:

Outlets are passages made through a parapet, or an enclosure of a gorge, for the service of the work.  They should, in all cases, be made in the least exposed part of the work.  Their width need not be more than six and a half feet, when used only for the service of the work; but when they serve as a common passage for wagons, &c., in the case of the intrenchment crossing a road, they should be at least ten feet wide.

Clear definition.  And some clear specifications with the idea width established at either 6 ½ feet, for “walk out” outlets, or ten feet, for “ride out” outlets.  That established as a rule of thumb, we turn to the structural components and advice for building these outlets:

When cut through the parapet, the sides receive a slope of three perpendicular to one base, and are riveted with sods, &c.

A gate, termed a barrier, serves as an enclosure to the outlet.  The framework of the barrier is made like an ordinary gate, consisting of two uprights, or stiles, a cross-piece, or rail, at the top and bottom, and a swinging bar, or a diagonal brace. Upright palisades, about seven feet long and four inches thick, are spiked to the frame about four inches apart; they are finished at top with spikes. A barrier, thus constructed, will not offer a shelter to the enemy should he attempt to cut it away.  The barrier is hung on hinges like an ordinary gate.  The posts of the framework should be very solidly braced to support the weight of the barrier.

Figure 41 illustrates such a barrier:

PlateVIFig41

Yes, they sell these as pre-fabricated products at Home Depot and Lowes.  Well… not exactly to military specifications.  But you get the point, the base form is a simple gate. For the annotations, Mahan offered:

  • A A – posts to which the gate is swung.
  • B B – the uprights of the gate.
  • c c’ – the upper and lower cross pieces. (c’ seems to have been left off).
  • D – the diagonal brace.
  • E – the bar of the gate.

Note also the mention of spikes on the gate. Specifically palisades.  These were not intended to impale an attacker, but rather to keep the attacker’s reach away from the structure of the gate.  So drop all those Medieval notions there.

Continuing, Mahan offered,  “A cheval-de-frise is sometimes used for a barrier, it presents but a trifling obstacle.”  So let us relegate that to the level of lazy engineering.

But just keeping the enemy at arms length was not enough.  One also had to protect the outlet from cannon fire. Toward that end:

The outlet should be covered by a mask, thrown up either on the interior, or on the exterior, to prevent the enemy from firing through it into the work.  A traverse is thrown across it, if placed on the interior.  Sufficient space should be left between the traverse and the parapet for the passage of a gun.  The length of the traverse is arranged to prevent the enemy from firing into the work, by an oblique fire through the outlet.  The traverse may be of earth or of wood; in either case it should be arranged for defense to enfilade the outlet. In some cases, and it would generally be safest, a barrier is erected between the parapet and the traverse, on each side of the outlet.

Figure 42 provides us Mahan’s suggested layout of the masking traverse:

PlateVIFig42

From the key for this figure:

  • O – the passage or outlet through the parapet.
  • P – (to the left of “Fig. 42.”) the passage between the parapet and the traverse
  • T – the traverse

Note Mahan gave us 6 ½ feet between the parapet and traverse for “P”.  We also see the prescribed cross fires built across the passage.

Mahan went on to suggest more elaborate defensive arrangements to protect important passages.  “In very frequented passages, a redan or a lunette, is thrown up on the exterior to cover the outlet, and thus ensure its safety in case of surprise.”  These arrangements followed the standard configurations for faces and flanks.  No doubt, such added more work for the defender’s labor force, as they would be clearing and leveling both front and rear.

The important take away with respect to passages is how a necessary weak spot in the defenses would be turned into a strong point by way of barriers, traverses, and other cover.

(Citations from Dennis Hart Mahan, A Treatise on Field Fortifications, New York: John Wiley, 1852, page 61-2.)

Fortification Friday: Interior Arrangements, starting with armaments

The next aspect of field fortifications to consider are the interior arrangements.  Thus far most of our focus has been towards the exterior, with the exception of the traverses, and what could be done to block or stop the attacker.  With the interior arrangements, the engineer would consider what could make the defenders’ job easier and, shall we say, more comfortable.  Mahan prefaced his lesson on interior arrangements by calling attention to such factors:

Under the [heading] of interior arrangements is comprised all the means resorted to within the work to procure an efficient defense; to preserve the troops and the material from the destructive effects of the enemy’s fire; and to prevent a surprise.

You are probably thinking, “protect the troops?  Isn’t that what the parapet does?  Doesn’t the ditch prevent surprise?”  Well… yes… you might look at it from that standpoint.  But what Mahan was calling attention to here were the structures and features which were internal to the works and designed to improve the nature of the defense.  As such “within the work” is the important phrase to consider.  But, keep your questions in mind as we work through this topic, as we will revisit shortly.

Mahan continued to offer a list of classes of these interior arrangements:

The class of constructions required for the above purposes, are batteries; powder magazines; traverses; shelters; enclosures for gorges and outlets; interior safety-redoubt, or keep; and bridges of communication.

From that we have a subdivision:

All arrangements made for the defense, with musketry and artillery, belong to what is termed the armament.

So we have a name for structures to support things that shoot.  Armaments.  Just for the context of these field fortification discussions, OK?

The armament with musketry is complete when the banquette and the interior and superior slopes are properly arranged, to enable the soldier to deliver his fire with effect; and to mount on the parapet to meet the enemy with the bayonet.  For this last purpose stout pickets may be driven into the interior slope, about midway from the bottom and three feet apart. The armament with artillery is, in a like manner, complete, when suitable means are taken to allow the guns to fire over the parapet, or through openings made in it; and when all the required accessories are provided for the service of the guns.

So… yes the parapet’s design can be considered part of the interior arrangements.

Mahan continues with this profound statement:

The armament with artillery is a subject of great importance….

You got me at “great importance.”

Oh, wait, I cut the professor off.  He has more on this ….

The armament with artillery is a subject of great importance, because it is not equally adapted to all classes of works.  Experience has demonstrated that the most efficient way of employing artillery, is in protecting the collateral salients by a well directed flank and cross fire, which shall not leave untouched a single foot of ground within its range, over which the enemy must approach.  It has moreover shown, that a work with a weak profile affords but little security to artillery within it; for artillery cannot defend itself, and such a work can be too easily carried by assault to offer any hope of keeping the enemy at a distance long enough to allow the artillery to produce its full effect.

The logic here is “form should follow function.”  If the intent is to have artillery fire on the enemy in order to break up the attack, then a flank fire is recommended.  And that artillery should blanket the approaches with fire… “shall not leave untouched a single foot….”  Artillery sits at the top of the list when making decisions about weapon placement.  It is the most effective, man per man, weapon for influencing the battlefield Not necessarily saying “killing” or producing causalities, but influencing the other side’s actions.  Yet, artillery’s influence is best gained over longer ranges.  Thus the need to form works that not only provide the artillery a measure of protection but also keep the enemy at greater than small arms length (range).

The best position for artillery is on the flanks and salients of a work; because from these points the salients are best protected, and the approaches best swept; and the guns should be collected at these points in batteries of several pieces; for experience has likewise shown, that it is only by opening a heavy, well-sustained fire on the enemy’s columns, that an efficient check can be [given] to them.  If only a few files are taken off, or the shot passes over the men, it rather inspires the enemy with confidence in his safety, and with contempt for the defenses.

Sun Tzu should have said it!  Don’t let the enemy become contemptuous of your defenses!

Consider the “best practice” offered by Mahan.  By placing artillery on the salients, the guns were out of the direct line of the attacker’s fires while being placed behind the various, and likely complex, defensive works on the “horns” of the bastion.  And artillery shouldn’t be parceled out as singles, but rather massed and inter-operated to multiply the effect.

All this is great theoretical talk.  Everyone would agree massing artillery is best.  But now we have a practical problem on the parapet.  With infantry, the parapet works fine to protect most of the body, provide cover to crouch behind when reloading, and, if the fight is close, an orientation for the bayonets.  But artillerymen cannot “crouch” an artillery piece.  And when servicing the weapon, they are exposed. Furthermore, there are all sorts of problems bringing 12 pound or 24 pound or larger projectiles up to the gun.  So to make the big guns work best, one must make arrangements.. in the interior…. And those arrangements Mahan identified under the classification of “batteries.” We’ll look at those next.

(Citations from Dennis Hart Mahan, A Treatise on Field Fortifications, New York: John Wiley, 1852, pages 51-2.)