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Brick Sizes at the Fortress of Louisbourg, 1725 through 1744-1745


Eric Krause

Krause House Info-Research Solutions

March 6, 2005

The common brick in use at the the Fortress of Louisbourg, beginning at least as early as 1725, and in particular, from 1731 through 1744-1745 was one that had been imported through Boston, Massachusetts.

Les briques que l'on fait icy estant fort petites, et tres mauvaises, et qui tombent en poussise mont fait prendre le parti den faire venir de baston, affin de faire de beaux en bons ouvrages ... [SOURCE] C11B, Volume 7, November 10, 1725, f. 345v [SOURCE]

During the Louisbourg period (1713-1758), French builders chose hand made bricks either produced on Isle Royale or imported from New England (though in 1722, 8,000 bricks of [8] pouces long may have been ordered from France. [Source] 1E99, March 18, 1722, p. 284 [Source] In the early years, the only available bricks came from a kiln at Port Toulouse (St. Peter's), set up circa 1716. [SOURCE] Bibliotheque Genie, Manuscript 125, 1717, p. 110; See also C11B, Volume 3, 30 December 1718, folio 120; C11C, Volume 15, item 69, 22 December 1716. [SOURCE]

However, its product was of an inferior quality, being dry and mixed with small stones, and, in 1723, declared too soft. [SOURCE] C11B, Volume 27, 1727, folio 315v; Archives Genie, Article 14, no. 43, 20 November 1751; C11B, Volume. 06, 1723, ff. 310-319. [SOURCE] This brick appeared to be 8 pouces* thick [... les briques du Port Toulouse estaient payee il y en avoit plus de 20000 mil et 8000 dans le magazin du Roy ce qui fait 4 tois et 1.3 cube et 37 quarree sur 8 pouces d'epaisseur ... [SOURCE]  C11B, Volume 3, December 30, 1718, f. 123v [SOURCE]

To fill the gap, a New England imported brick came to dominate the building scene from the 1730's to the final fall of Louisbourg in 1758. Meanwhile, in the early 1750's, with mixed results, kilns were set up at Spanish Bay (Sydney), and then, more successfully, in the Mira area. [SOURCE] Dilys Francis, "The Mines and Quarries of Cape Breton Island During the French Period, 1713 - 1760", (Fortress of Louisbourg, November 15 1965), pp. 20 - 21 [SOURCE]

In 1737, the "Devis pour la maison Duperrier-Rodrigue" provided the following specifications:

... 8e

... Tous les cheminé Seront fait de Bonne brique bien quitte de huit pouce de long Sur quatre de Large le tout maçonné de mortier de chaux et de Sable fin bien endhuit par dedans de mesme mortier le plus proprement que faire Se pouras ... [SOURCE] G2, Volume 184, 1737, ff. 392-394 [SOURCE]

According to Louis Franquet, Director of Fortifications for the whole of New France, the Isle Royale brick of  1753 from Spanish Bay measured 8 pouces 3 lignes by 4 pouces 2 lignes by 2 pouces l/2 ligne [8.7944 x 4.4416 x 2.1764 inches or i.e 8 51/64 x 4 29/64 x 2 5 1/2/32 inches]. However, at this time, the imported New England brick measured only 7 pouces long by 3 pouces 6 lignes wide, by 1 pouce 8 lignes thick [7.462 x 3.7308 x 1.7760 inches or i.e 7 15/32 x 3 47/64 x 1 25/32 inches). [SOURCE] C11B, Volume 33, October 9, 1753, ff. 464 - 465 [SOURCE]

Normally, when one sees a brick dimension, it is considered nominal in that it includes the thickness of the mortar joint.  Thus, physically, the actual brick is a usually smaller. For example, a brick described as being 8 inches long but laid with a 3/8 inch joint would actually have measured only 7 5/8 inches in length when in hand.

Now, how does the 1753 Isle Royal descriptions fit with this rule? 

Significantly, Franquet's initial cost calculations were based entirely on the price per imported brick (e.g. 21 livres 10 sols per 1000 English bricks), thus clearly indicating that the above dimensions were their actual physical size. When he then further stated that experience indicated that it took 7938 (at a cost of 170 livres 13 sols 4 deniers  2/25) of the smaller English brick to occupy the same 1 toise cube of space that 4860 of the larger local brick took, only then was he taking into account the mortar joint. Moreover, he was to later observe, that within that same cubic space, the local brick would have required 2/7th less mortar than the English brick, thus increasing entrepreneurial profits. Of interest, in 1753, the charge-back, which would have included both the bricks and the required mortar, in a construction Devis with Claude Coeuret for maintaining the King's works, was 120 livres per cubic toise. ( [ASQ, Surlaville Papers, October 1, 1753] 

Although brick imports from New England were to continue in the 1750's, there was clearly a renewed interest at this time in local bricks, and that, in 1753, when they cost 27 livres per 1000 (notwithstanding Coeuret's even cheaper arrangement), the price was most competitive. According to Franquet,  a charge of as much as 35 livres per 1000 would have returned the same price as those from New England. [C11B, Volume 33, October 12, 1753, f. 237; C11B, Volume 33, October 9, 1753, ff. 464 - 465.]

In England, government statutes in force during the Louisbourg period set the size of the common brick in inches at 9 in length by 4 1/2  in width by 2 1/4  in thickness. [SOURCE] John Muller, A Treatise Containing The Practical Part of Fortification, (London, 1755), p. 102.; See also, Calder Loth, "Notes on the Evolution of Virginia Brickwork from the Seventeenth Century to the Late Nineteenth Century," in APT Bulletin, 6:2 (1974), pp. 82 - 83. Loth suggested that the width was 4 1/4 (4.25) inches. [SOURCE]

In the American colonies, its bricks often measured this English "statute" size as well. [SOURCE] Harley J. Mckee, Introduction to Early American Masonry, Stone, Brick, Mortar and Plaster, National Trust/Columbia University Series on the Technology of Early American Building, p. 48 [SOURCE]

However, ordinary French bricks measured 8 (sometimes 9) pouces in length by 4 (sometimes 4 1/2) pouces in width by either 1 or 1 1/2 (often for laying in the place of pavé) or 2 pouces in thickness. [SOURCE] C.E. Briseux, L'Art de Bâtir des Maisons de Campagne, (Paris, 1743), p. 46; Belidor, La Science des Ingenieurs dans la Conduite des travaux de Fortification et D'Architecture Civile, (Paris, 1729), p. 7; Architecture Moderne ou L'Art de Bien Bâtir, (Paris, 1728), p. 23; J. F. Monroy, Trait d'Architecture Pratique (Paris: 1789), p. 15. 
In France, a cubic toise of mortared brickwork equalled 4600 bricks (8x4x2 pouces) or 520 when used in one toise quarre'e of work of one brick thickness (i.e. 8 pouces). At this time, French bricks weighed about 4 livres each - Belidor, p. 27; See also J.F. Blondel, Cours d'Architecture, (Paris, 1777), p. 169. He stated that they weighed only 1 1/2 livres. [SOURCE]

In Massachusetts, in 1711, according to the consolidated act, some things were to change, including brick size:

That Clay for the making of Bricks shall be digged before the tenth of December yearly; and shall be turned over in the Month of February or March next ensuing, at least twenty Days before it be wrought; and then well and thoroughly wrought. And no Person shall temper his Clay with salt or brackish Water; nor digg any Clay in any Place where the salt Water comes in. ... That the Size of Bricks shan't be less than nine Inches long, four Inches and a Quarter of an Inch Broad, and two Inches and an Half Inch thick. And all Moulds to be used for the making of Bricks, shall be made agreable to these Sizes: That is to say, not less than nine Inches and a Quarter of an Inch long, four Inches a Quarter and a Half Quarter of an Inch broad, and two Inches and Half an Inch deep, within Side; being well shod with Iron, and sealed by the Sealer to be appointed, as is herein directed: so that the Bricks may hold out the Dimensions prescribed as aforesaid, as near as may be when burned ... [SOURCE] Acts and Laws of His Majesty's Province of the Massachusetts-Bay in New-England (Boston, 1759), 1711, pp. 172-173 [SOURCE]

In Boston, in the 1760"s at least, some bricks measured in inches 8 long by 4 wide by 2 thick. Those placed on the outward face of the building were to be struck in sand. [SOURCE] George Francis Dow, The Arts and Crafts in New England, (Topsfield, 1927), pp. 219 -220 [SOURCE]

As late as 1772:
WANTED, for building a New Meeting-House ...

... 800 Thousand Bricks eight Inches long four wide and two thick, to be made of tough well-tempered Clay, and well burnt, one quarter Part of them to be stuck in Sand for the outward Face of the Building. Four Thousand Sand Bricks for outside Arches, nine Inches long four & half wide and two & half thick. One Thousand Water-table Bricks made in Proportion to the Others. One & half Thousand O G Bricks for Facias, 8, 4 & 2. ... [SOURCE] Boston News-Letter, February 20, 1772 [SOURCE]

1 French Ligne  =    .0888 English Inches [3/32]    with 12 ligne to a pouce
1 French Pouce  = 1.0656 English Inches [1 1/16]