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 B: The Trace

The evolution of the trace can be divided into three periods. In the first, Colonel Nicolls formulated his initial design and, after some experience with the construction, altered parts of it. In the second, Colonels Boteler and Jones and Captain Peake re-designed much of the work, and after a lengthy and complicated series of events, succeeded in settling the general outline of the fort as it now stands. In the third period, Colonels Calder and Savage made suggestions to improve the design still further, and succeeded in making many alterations.

Nicolls's original design was for a fort in which the opposite fronts were identical. There were four demi-bastions of the same dimensions; two curtains (east and west) and four ravelins, one opposite each front. The whole was surrounded by a ditch bounded by a counterscarp and by a gallery containing casemates of reverse fire, opposite the four bastion salients. Countermines were placed at regular intervals along the gallery.

The interior of the fort, because of its shape, was cramped. A large portion of the available space was to be taken up by two cavaliers and the powder magazine. The latter, a survival from the previous fort, was located at the southern end of the east curtain. The two cavaliers were both to be in the north end of the fort. They were to be of identical size, each containing seven two-storey casemates, and were to face west and north.

Beneath the ramparts, Nicolls placed 16 casemates of defence in pairs, two flanking each of the ravelin ditches. These were intended primarily for defensive purposes, although they could also be used for accommodation and storage.

The western ditch was flanked by a caponier which led from the west curtain to the guardhouse in the gorge of the ravelin opposite. This ravelin was flanked by two rudimentary places d'armes, one above each counterscarp re-entrant.

Nicolls proposed three major alterations to this basic scheme. On a suggestion from the Assistant Inspector General of Fortifications, he rearranged the cavaliers, placing three of the casemates intended for the north cavalier in the south end of the fort, and leaving the remaining four in their original location. He altered the trace of the northern front slightly to allow the inclusion of an old well within the bounds of the fort. This was the origin of the asymmetrical shape of that front and the off-centre reentrant angle of both the front and the ravelin opposite.

Nicolls's most radical alteration was his proposal for a redan on the eastern front. This was also at least partly out of consideration of the water supply, since it allowed yet another old well to be included in the body of the fort.

The disasters of the early 1830s led to a re-examination of the whole design. When the controversy was finally settled in 1838, fundamental changes had been made. The north and south cavaliers, the caponier and the places d'armes were all discarded. The counterscarp gallery and the ravelin guardhouses were redesigned. The casemates of reverse fire were abandoned and only half the countermines (those on the north and west fronts) were retained. The old magazine was judged unfit, owing to its location and height, and replacement magazines were designed for the gorges of the western bastions.

The most fundamental change was the introduction of dwelling casemates. Of Nicolls's original 16 casemates of defence, 4 had disappeared with the introduction of the redan. To the 12 remaining were added another 26, including 12 two-storey dwelling casemates in the redan. The west cavalier was retained, but was slightly re-designed to include cooking casemates at each end.

After 1838 there were no essential alterations to the shape of the fort. In 1843 Colonel Calder added a number of features, including 19 casemates, storage cellars (under the redan), the magazine porches and the rooms over the cavalier cooking casemates. He also redesigned the roofs of the magazines and ravelin guardhouses.

In a later estimate (1846) Calder attempted to provide for the services needed for the proper functioning of the fort, including tanks and drains for the water supply, lightning conductors for the magazines, and flagging for the magazine areas. These proposals were, in the end, all altered to meet changing conditions. The whole of the water supply system, for example, was changed several times before the final version, a complicated system of drains and storage tanks, was installed in the early 1850s.

Calder's final contribution to the site was a major re-designing of the west ravelin, which, because of earlier collapses, had to be rebuilt. At this time (1846) the final form of all three ravelins was settled. The guardhouse ditch was the most important addition Calder made to the two existing ravelins.

After 1850, all changes were made in response to the needs of the moment. The final version of the cavalier roof and chimneys, for example, was arrived at in a desperate attempt to keep the barrack space in the building dry.