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Canadian Historic Sites: Occasional Papers in Archaeology and History No. 17

The Halifax Citadel, 1825-60: A Narrative and Structural History

by John Joseph Greenough

Appendix G: Walls

The Escarps

Of all the individual features of the Citadel, the escarp walls caused the most grief. Designed to inadequate specifications, they were, from the first, likely to collapse. They were redesigned several times and were not entirely completed until the mid-1840s. Even then, substantial portions of the escarp wall were of dubious quality, and remained problematical right down to the completion of the work and beyond.

The origin of the problem is discussed more fully in the main part of this report. It should suffice to say that Colonel Nicolls proposed escarps of a thin profile in order to save money. His proposals were approved, and the first call for tenders for the construction of the escarps was issued on 12 November 1828.1 The escarp to be built by contract included the two faces of both the western demi-basstions and the flank of the southwest demi-bastion. The walls were duly constructed in the summer and fall of 1829, and Nicolls pronounced himself satisfied with the work. Late in the fall of the same year, he called for tenders for another large portion of the escarp.2 The work this time was on the northern and southern fronts and was virtually completed by the onset of the winter of 1830-31. Nicolls again issued specifications for another stretch of wall, and this time, having expressed his complete satisfaction with the work done by the two contractors during the preceeding summer, allowed the contracts to be given without tenders to the same gentlemen.3 In all, the three sets of contracts called for the construction of 2,120 feet of wall; and, had all gone well, almost all the escarp walls of the body of the Citadel would have been complete by the fall of 1831. Things did not, however, go well. On 9 December 1830, 51 feet of the escarp in the southwest demi-bastion collapsed.4 A few weeks later, another 70 feet of escarp (this time in the northwest demi-bastion) also collapsed.5 The consequences of these two events were extremely serious; they led to a questioning of the entire original design, and, ultimately, to many of the problems which delayed the completion of the Citadel for almost 15 years.

The difficulties encountered in building the escarps did not by themselves cripple the progress of the work. A second factor was involved. In September 1831, Nicolls proposed the substitution of a redan for a curtain and ravelin on the eastern front.6 Even as he made the suggestion, the last of the escarp on the north, south and west fronts was being completed. By the fall of 1831, the escarp was complete to the end of what would have been the east face of the eastern demi-bastion (in the original plan) which was now the eastern face of the salients. As long as there was uncertainty about the future of the eastern front, no more escarp could be built.

Two very different kinds of escarp were built in the summer of 1831. The last set of contracts was honoured and, for the last time, civilian masons laboured on the escarp walls. They built the curtain and parts of the salients (as they were to become). The escarp built in these areas, though somewhat more substantial than the work which had collapsed, was still very like it.7 But the escarp design for the rebuilding of the breach in the northwest demi-bastion was entirely different. The replacement wall was designed and constructed by the Engineer department, and was a full three feet thicker at the base than the original wall had been. In addition, the new wall was buttressed up to its full height; the old buttresses had stopped at the top of the batter.

The rebuilding of the failed right face of the northwest demi-bastion in the summer of 1831 led to a ridiculous situation, wherein part of the wall was almost immeasurably stronger than the adjacent sections — a fact which made it obvious that some major rebuilding was necessary. There was, however, neither money nor authority for rebuilding, and the entire matter waited for the approval of a revised estimate for the completion of the work. This was not forthcoming until 1838. In the meantime, only the breach in the northwest demi-bastion was rebuilt.

The provisions of Colonel Jones's revised estimate (1836) finally settled the issue. The estimate definitely established the shape of the fort (the proposal for a redan was accepted) and estimated for the necessary repairs and renewals in the western bastions. The work in the western bastions was calculated to involve the following:

Right face N. W. Bastion —62 feet
Left face N. W. Bastion —60 feet
Flank in N. W. Bastion —434 feet
Right face S. W. Bastion —200 feet
Left face S. W. Bastion —63 feet
Flank S. W. Bastion —35 feet8

The estimate also provided for escarps to close up the eastern front. In all, Jones estimated for the construction or reconstruction of all of the redan, about 45 feet of the eastern faces of both the eastern salients at the redan ends, virtually all of the southwest demi-bastion (except for part of the flank) and about a third of the northwest demi-bastion. About another third of the northwest demi-bastion had already been rebuilt. With the execution of the provisions of Colonel Jones's estimate, therefore, only a comparatively small portion of the escarp built before 1832 was left standing. This included the whole of the west curtain, about an eighth of the flank of the southwest demi-bastion, the south front escarp between the casemates of defence in the southwest demi-bastion and the salient, the corresponding stretch on the northern front, and the eastern faces of the eastern salients from the salient to within about 45 feet of the redan.

Three sorts of escarp wall were proposed in the revised estimate. The type intended for the rebuilt sections was a modified version of the escarp used in the rebuilding of the breach in the northwest bastion. The escarp proposed for the redan was designed especially for a casemated rampart, and was therefore somewhat thinner than that proposed for the western bastions, which were to be uncasemated. At the salient of the redan, there was a short stretch of escarp (220 feet) which had no casemates behind it. Since this was also the highest escarp wall in the fortress, it required greater strength than the rest of the redan escarp and was designed accordingly.

The new escarp walls were completed by 1843. In that year, however, Colonel Calder decided that the old escarp in the northeast salient was no longer adequate. "the Climate having . . . so acted on the Masonry as to render it doubtful whether it will sustain the weight & pressure of the ramparts."9 Part of the rampart in question had already been casemated, and Calder proposed to casemate the rest. He proposed to tear down the old escarp to its foundation (which would, he thought, be adequate to bear the weight of the new wall) and erect on it an escarp similar to that in the redan. Like the redan, two escarp sections were designed — a relatively thin one for the casemated sections and a thicker one for the salient and easternmost part of the right face of the northwest demi-bastion, which would have to bear the full weight of the rampart.10

All of the Citadel escarps were completed in their final form by the end of 1847, and were little modified thereafter. The top of the escarp and its coping were altered in the casemated portions of the rampart to assist in the drainage and staunching operations, but this had no visible effect on the shape of the wall.

The implementation of the provisions of the 1843 estimate left only small portions of pre-1832 masonry escarp standing, and these were left alone until the early 1850s. By then, most of the old masonry had begun to look exceedingly decrepit. Some of the junior engineer officers began to wonder whether it would not be necessary ultimately to rebuild, but, in the end, the old walls survived, and the only work undertaken on them was in repointing them.11

Even as the walls were being repointed, they attracted the attention of Major General Le Marchant, who, in drawing up the questions put to the 1856 committee investigating the state of the Citadel, put particular emphasis on the state of the masonry. There were no fewer than 20 questions on the subject, ranging from general queries to specific and pointed enquiries about the type of stone used and the wording of the contracts under which (as Le Marchant thought, erroneously) most of the old work had been done. In the end, the committee delivered itself of the opinion that the walls, though hardly all that they should be, could, with care, be expected not to fall down "for many years."12

The Counterscarp

Work on the counterscarp was begun in 1829 and was not completed until 1848. Unlike some of the other elements in the Citadel the long delay was not the result of faulty original design. The main reason was that the counterscarp, being one of the less important features in the fortress, was allowed to languish while the more essential elements were completed. Nonetheless, the design changes in the mid-1830s did result in a radical alteration in the shape of the counterscarp gallery, and the construction of it and the counterscarp was not without incident.

The counterscarp, gallery and mines served three separate functions. The counterscarp covered the escarp from distant cannon fire; the gallery provided flanking fire for the ditch and access to the mines; the mines were intended as a defence against sapping operations by a besieging army. The gallery also provided additional structural strength for the counterscarp. In the original design of the Citadel, the counterscarp was provided with a uniform, continuous-arch gallery running the entire circumference of the fortress. At regular intervals on all four fronts, countermines branched off the main gallery. At eight points the gallery widened, at each of the four demi-bastion salients and at each of the re-entrants on the east and west fronts. The four stretches of enlarged gallery at the re-entrants were opposite the sally ports, and it is possible that they were intended as a sort of entrance hall to the rest of the gallery. Unfortunately, none of the surviving plans shows any access doors leading to the gallery at any of the re-entrants, so that there is no way of proving this hypothesis.13 The four stretches of enlarged gallery at the salients were the so-called casemates of reverse fire. They were intended to provide concentrated flanking fire for the ditch, and were particularly important on the north and south fronts, where there was no other source of flanking fire.14

By the time of the wall failures and the subsequent crises of the early 1830s, about two-thirds of the counterscarp and gallery on the west front and about three-quarters of that on the north front were either completed or under construction.15 Indeed, when Colonel Boteler took over, the counterscarp was one of the few parts of the fortress which he felt he could proceed with without altering the original design.16 He soon found that he was wrong. The ditch opposite the left face of the northwest demi-bastion deepened between the flank and the salient. This, in turn, meant that the loopholes would be 6 ft. 3 in. above the floor of the ditch at the west ravelin end of the counterscarp and 9 ft. 3 in. above it at the salient. Colonel Nicolls's plans were, as usual, ambiguous about his intentions for this particular stretch of gallery, and Boteler was forced to write London to request an opinion.17 The correspondence on the subject dragged on for months — also, as usual. At one point. Boteler dispatched a plan of the gallery as designed by Nicolls, showing the alternative arrangements.18 At another point, Sir Alexander Bryce, the Inspector General, sent a plan showing his proposed alterations in the manner of construction.19 The Inspector General's plan is interesting, since it provides a clue for the changes which were ultimately made in the shape of the gallery. General Bryce feared that those defending the gallery in case of attack would be vulnerable to grenades thrown by attackers in the ditch, and this, presumably, was the reason for the suggestion for a segmental or compartmentalized gallery contained in his plan. The proposal still envisaged a continuous arch, but it also envisaged dividing the gallery into sections, each one containing three loopholes. This proposal was not adopted, but it did provide the germ for the major alterations proposed for the gallery a few months later.

The casemate of reverse fire opposite the northwest demi-bastion continued to give trouble throughout the summer of 1832. The engineers soon discovered that the casemate was being constructed on "made ground" — that is, ground which had been built up with earth from elsewhere. This meant that the footings had to be sunk to relatively great depths in order to be secure.20 As the counterscarp neared the salient, the problem got progressively worse. From a standard 6 ft. 6 in. footing, the depth was increased to 9 ft. 9 in., to 11 ft. 9 in., and finally to a full 14 ft.21 This added considerably to the expense, and seems to have absorbed most of the funds allotted for that particular stretch of gallery. It is not entirely certain, but it seems likely that, when the footings were completed work on the counterscarp and gallery stopped and was not begun again for another six years.

In the meantime, the whole question of the shape of the fort was being thrashed out. In the winter of 1832-33 no fewer than seven different estimates for the completion of the Citadel were drawn up. All seven of them, in one way or another, were based on the assumption that economies had to be made, and one feature of the fortress which could be built relatively cheaply was the counterscarp gallery.

The various proposals put forward in the winter of 1832-33 mostly involved the elimination of elements of the original plan. In one of Boteler's estimates, a proposal was put forward to build the gallery and mines as planned on the west and north fronts and omit them entirely on the other two.22 Boteler was, however, not very happy with this arrangement, and drew up a second estimate with the intention of showing the cost of (among other things) the entire gallery and mines as originally planned.23

Captain Peake's ideas were more radical. He wanted to leave out not only the gallery and mines, but also the counterscarp itself on the eastern front.24 This was a little extreme for anyone, and, in the end, a compromise was reached. In Colonel Jones's estimate, drawn up in the winter of 1833-34, the gallery was reinstated along the entire circumference of the fort, and only the countermines intended for the south and east fronts were deleted.25 This proposal was accepted.

In the course of sorting out the extent of gallery required, the whole basic design was altered. The person most responsible for the changes seems to have been Captain Peake. His design for the gallery consisted of a series of linked arched cells with both counterscarp and rear wall of the gallery sharing a common footing.26 The design was adopted by Jones, who altered it somewhat by redesigning the dos d'anes and doors; in this modified form, the design was accepted.27 The reasons for the change are not easy to determine. One supposes that at least a part of the reason for Peake's design was its resemblance to General Bryce's suggestion. In addition to this, the new design was believed to be cheaper to build than the original.

After the revised version of Jones's estimate was approved in 1838, work was resumed on the counterscarp and gallery and continued for another ten years. Most, but not all, of the gallery constructed after 1838 was built to the new design. A few portions were built to the original specifications. The casemates of reverse fire were abandoned altogether, and the segmental design was used at the salients, with the addition of more loopholes.

The troublesome casemate of reverse fire at the northwest demi-bastion salient may well have been built as a hybrid. The footings, as we have seen, had been constructed in 1832 before the design for the gallery was changed. The gallery itself, however, was built to the new segmental pattern. Since the new pattern was designed with a different type of footing, one can only conclude that the gallery at the salient deviated somewhat from the standard plan. Either that, or the counterscarp has, at that point, the phenomenal footing of 14 ft. by 12 ft.

The Rampart Retaining Wall

The first design for the rampart retaining wall was the work of Colonel Nicolls, As far as I have been able to determine, none of the retaining wall was ever built to Nicolls's specifications, but it seems likely that his design would have been as inadequate for the retaining wall as the escarp designs were for the escarps. When Boteler and Peake drew up their revised estimates in 1832-33, the retaining walls they proposed were substantially thicker than Nicolls's.28

It was Captain Peake who suggested the final design of the retaining wall for the uncasemated part of the rampart. The retaining wall was subject to the same stresses as the escarp, and there was some difficulty in designing a wall which could bear the weight of the ramparts without being excessively expensive. Peake's solution was to provide the wall with arched recesses for greater strength. This allowed the wall to have a thin profile (between 2-1/2 and 3 ft.). The similarity between the retaining wall designed in this manner and the segmental pattern counterscarp gallery (also Peake's design) is striking; indeed, it seems likely that the one suggested the other.29

Colonel Jones, in drawing up the version of the revised estimate which was finally accepted, borrowed Peake's design. Virtually all the documentary material we possess on the subject of the retaining wall is contained in Jones's estimate. He provided for an arched retaining wall for the west and south fronts and for parts of the east and north fronts.30 The remaining sections of the retaining wall were included in the estimate for casemates. The retaining wall for the redan, for example, was built as an integral part of the redan casemates.31

When additional casemating was proposed in 1843, no mention of the retaining wall was made in the estimate.32 This leads to the supposition that the existing retaining wall was adapted to meet the needs of a casemated rampart. At the same time that the additional casemating was decided upon, it was found necessary to rebuild the retaining wall in front of some of the casemates at the north and south ends of the curtain, and the plans and estimates for this service are the best we possess for the type of retaining wall in use for casemated ramparts.33

The retaining wall was altered somewhat in the course of the staunching operations.34 After this, no additional work was done on them until the committee examining the state of the Citadel investigated them in 1856, and reported that the walls in the southeast salient were slightly defective.35 It was not until 1875, however, that the engineers felt it necessary to make any major repairs. In that year, a proposal was submitted for the reconstruction of the retaining wall in the southeast salient. The plan drawn up to accompany the proposal is the only one available which gives accurate information about the dimensions of the retaining wall and recesses as they were actually built.36 The plan also shows something of the variety of uses to which the recesses were put.

The major provision of the rebuilding scheme was the addition of buttresses between every second recess. With the acceptance of the proposal and the construction of the buttresses, the retaining wall reached its final form.

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