As we continue to compare and contrast the pre-war writings of Dennis H. Mahan with the post-war instructions of Junius B. Wheeler, let’s move from arrangements for the artillery to that of the infantry on the parapet. Mahan, like his contemporaries, left the infantry on a bare parapet, with a firing step on the banquette that would allow them to step-up to the crest and fire over. Little else was deemed necessary. But experience of the Civil War indicated something more was indeed necessary. Wheeler discussed this under the heading of “loopholes”:
Loop-holes. – Troops on the banquette, when in the act of firing their pieces, are frequently exposed to the fire of the enemy’s sharp-shooters. Under these circumstances, expedients must be devised to protect the men, without interfering with their fire. The expedient which is most generally used, is that of an improvised loop-hole. The loop-hole is made, in this case, by arranging two or more rows of sand bags, placed upon the parapet and filled with earth, so that the top row will be higher than the men’s heads, and so as to leave intervals between the bags in the lower rows, through which the men can aim and fire their pieces.
Figure 28 illustrated this arrangement:
Let’s walk through this passage, as it offers another glimpse into the changing doctrine applied to the battlefield. Right from the start, we see something “non-Mahan” as a condition. In those pre-war days where the Napoleonic battlefield framework was in play, musketry was generally used in mass. Volley fire, by attacker and defender, was the expected means of delivering those lead projectiles. In that framework, working a musket into a gap in sandbags would slow down the delivery of a volley.
But Wheeler alluded to a change in how musketry was used. Instead of massing fires in volleys, the Civil War armies employed much more individual fires. Skirmishing, of course, took on greater importance. And in these field fortifications, that translated to sharpshooting. More likely the attacker would employ this means of attriting the defender, instead of attempting a rush of the works.
This is not to say nobody ever thought of putting sandbags on the parapet before the Civil War (or headlogs, which we’ll circle back to). But this is to say changes in the way musketry was delivered brought out a need to employ this feature (loopholes) as a standard fit on the parapet. Wheeler and his contemporaries didn’t invent the sandbag loophole. They simply introduced it to meet an evolving requirement. Yes, “innovation” does not always mean “invention.”
There were other ways to setup a loophole on the parapet of course:
Gabions are also used for a similar purpose. The gabions are placed in pairs upon the parapet and filled with earth, each pair being separated from the adjacent pair by an interval of about two inches.
And… field experience gave us even more options:
A contrivance adopted in the war of 1861-5, was quite effective for the same purpose. Skids were placed upon the parapet, with notches cut in them. A heavy log was placed on the skids, occupying a position parallel to the interior crest and just in contact with the superior slope. Notches were cut in the underside of this horizontal log and these were used as loop-holes. The openings to the exterior were made as small as possible, and in some cases were protected by small patches of boiler iron spiked upon the log. When exposed to artillery fire, earth was banked against the log.
We often hear this or similar arrangements called a “head log” in the writings of veterans. I am most curious that Wheeler didn’t use the term. And even more curious why Wheeler didn’t include an illustration! At any rate, he continued with this description, naming an “innovator” from the late war:
A wooden loop-hole was devised by Lieut. King (now Major) of the United States Engineers, which was used in 1864. It was practically a wooden hopper made of boards, placed upon the superior slope of the parapet, and covered with earth. The splay of the sole and the angle of the cheeks were made to suit the field of fire required.
The officer mentioned was Lieutenant William R. King. Brett Schulte has King’s report on Beyond the Crater, and a detailed report it is. The accompanying illustration matches to Wheeler’s description. For brevity, I’ll refer you to Brett’s excellent site.
Wheeler continued, with detailed requirements for these loopholes:
The exterior orifice of a loop-hole for musketry should be made as small as possible. A width of two inches and a height of five, is sufficiently large for ordinary purposes. The sides are sloped, and an inclination given to the bottom and top, according to the field of fire which is to be swept.
Now what is good for the musket should also be good for the cannons, right? Of course:
Embrasures are sometimes protected in a manner similar to this arrangement for loop-holes. Timbers are laid across the embrasure, covering the throat, leaving only room for the muzzle of the piece. These timbers are then covered by sand bags, by fascines, etc., to make them shot-proof. Sometimes the embrasure is filled with sand bags or fascines to mask it, these things being quickly removed when the embrasure is needed for use.
Thick wooden shutters, made bullet-proof, and placed on vertical axes, and iron shutters swung on horizontal axes, have both been used to close the throat of the embrasure.
In some cases, timber supports were extended back from the parapet and a covering of timber and earth placed upon them, protecting the gun from vertical and plunging fire. A gun thus sheltered is said to be case-mated.
Again we see the factor driving all this “innovation” and change – different types of fire were employed. Individual musketry … sharpshooting as it may be called… brought out the need for protection on the parapet. Vertical and plunging fire, which I have written about before, brought out the need for overhead protection. No new inventions are introduced here, rather the innovation lay in the way existing practices were employed.
(Citations from Junius B. Wheeler, The Elements of Field Fortifications, New York: D. Van Nostrand, 1882, pages 126-8.)