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Canadian Historic Sites: Occasional Papers in Archaeology and History No. 12

Lime Preparation at 18th-Century Louisbourg

by Charles S. Lindsay

Introduction to the Faubourg Lime-kiln

The Site

The faubourg lime-kiln was built into the side of a low hill outside the landward defences of the fortress, approximately 200 yards northwest of the Dauphin Demi-bastion, in the area known as the faubourg or suburb (Fig. 8). The terrain in this area is mostly marsh with a number of low hills of glacial moraine rising out of it. The hills overlook the fortress defences and were the sites of enemy batteries during both sieges of Louisbourg. The hill on which the lime-kiln stood was the closest to the town and was the site of the "Advanced Battery" in the first siege of 1745.1 To prevent the use of this hill a second time the French removed the top seven pieds in 1757. Apparently the precaution was effective since no battery was erected on this hill during the second siege the following year.

The effect of lowering the hill was to move the crest toward the south, where a complete natural stratigraphic sequence was revealed during excavation. On the north and west sides of the hill, by contrast, there was no A or B horizon, but merely a thin topsoil overlying the weathered surface of the C horizon, which was a yellow, stone-filled, glacial till.2


The first kiln on this site was built in 1755 according to a letter written by Franquet in that year.3 Lime-kilns were frequently built to supply lime for specific nearby construction projects, and in the years 1755 and/or 1756 the only major work in this area was the strengthening of the Dauphin Gate by the addition of a thick rampart made of rubble-stone set in mortar. This type of construction required a vast amount of mortar, yet prior to the building of this kiln, the nearest place where lime could be burnt was at the kilns near Rochefort Point on the far side of the town over three-quarters of a mile away. In addition to the problem of their location, Franquet also noted that these Rochefort Point kilns were small and badly built.4 These disadvantages made the construction of a bigger and better kiln near the site of the work most desirable.

One further advantage gained from this choice of location outside the town was that it avoided the problem of noxious fumes and the risk of fire associated with those earlier kilns built within the town boundaries. We have no documentary record of any edict banning the construction of kilns within the town of Louisbourg, but there may well have been such a restriction imposed after the return of the French in 1749 since all subsequent kilns were built outside the town limits. Certainly such restrictions were common in this period in many parts of Europe.

8 Plan of part of the faubourg in 1757 with the Dauphin demi-bastion on the left. The kiln was probably built to supply lime for construction work at the Dauphin Gate in 1755-56. From a plan entitled "Louisbourg en l'Isle Royale." (Original source unknown; copy on file at Public Archives of Canada.)

The development of the kiln can be divided into two stages (Fig. 9). In the first the kiln was a circular, open-topped structure built into the southeast side of the hill and, by the addition of banks around the upper parts of the wall, mostly subterranean. Its appearance was probably very similar to the kiln at the Royal Battery which shows the top 6 ft. of the wall above ground (Fig. 25, c). Leading from an opening on the southeast side, away from the prevailing wind, there was a sunken, stone-lined passageway with a wooden drain emerging from the end.

9 Plan of the faubourg lime-kiln. (click on image for a PDF version)

In the second stage the first kiln was partly filled and a second one built inside it. The latter was a more elaborate structure with three drawholes on the southeast, north and west sides. Access to the drawholes was gained by cutting alcoves through the wall of the first kiln after having dug passageways through the hillside to the base of the wall. These passageways, as much as 10 ft. deep in places and up to 15 ft. wide, were maintained by laying a wooden floor and by revetting the sides with timber framing and planking. The relatively large expense of these alterations on a minor structure such as a lime-kiln must have had some justification and this is partly to be found in the greater efficiency of the new design, which changed the method of operation of the kiln from flare to running by providing drawholes for withdrawing the burnt lime.

10 Section through the faubourg lime-kiln. (click on image for a PDF version)

In the previous section we have seen the advantages of the running kiln both in economy of operation and in its ability to provide a steady supply of lime. These improvements were partly offset in this kiln by the fact that it had considerably less capacity than the first; which suggests either that the main phase of construction was completed at the Dauphin Gate and the demand was less, or, more likely, that the first kiln had proved so inefficient that it was worthwhile to reduce the size of each load in return for a product of a better quality. There is no record of when the second kiln was erected or how long the first one was used. Neither could have had a very long life, however, since during the second siege in 1758 the French sallied out of the fortress on two successive nights to level the warehouse associated with the kiln and to demolish the kiln itself.5 From the excavated remains of the kiln, which was filled with rubble, it seems that demolition took the form of pushing in the top part of the kiln to prevent its use as cover by the besiegers. It is probable that the French also filled in the passageways to the drawholes, since the almost vertical sides remained when excavated. If they had been left open to the elements they would quickly have eroded to a shallow slope, as they did when left open for just one winter after excavation in 1968.

Thus the active life of the kiln was three years at most, compared with seven years for the kiln near Block 1 inside the town and an intermittent 20-odd years for those near Rochefort Point (see Other Lime Kilns at Louisbourg). Whether it was intended to use the kiln for longer is uncertain, but the large investments of time and money suggest that it was.

11 General view of the faubourg lime-kiln after excavation, looking northwest.

It is interesting that this is the only kiln known to have been built at Louisbourg after the arrival of a master limeburner in 1752.6 Perhaps it was his knowledge of the more sophisticated running kilns in France that led to the construction of the more elaborate second kiln.

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