Complete View of the Manners, Customs, Arms, Habits & Co of the Inhabitants of England, 1774, by Joseph Strutt.
3. Great Chesterford
“The original old wall of the city of London, was beyond doubt Roman; said to have been built by Constantine, which Dr Woodward, (who had an opportunity of examining it when Bishopsgate was taken down, and foundations dug for new buildings) thus describes. “From the foundation which lay 8 feet below the present surface, quite up to the top, which was in all near 10 feet high; it was compiled of layers of broad flat bricks and rag stone; the bricks lay in double ranges; each brick 1 inch 3-10ths thick, the whole layer with the mortar interspersed, exceeded not 3 inches: the layers of stones were no quite 2 feet thick of our measure: ‘tis probable that they were intended for 2 feet of the Romans, their rule being somewhat shorter than ours. To this was intermixed with the rag stone, was become as hard as the stone itself, and the thickness of the whole wall was a full 9 feet.” This description of Dr Woodward’s exactly agrees both in the measures and materials, with the Roman station at Chesterford in Essex, that I examined with the greatest care and circumspection, in the year 1772; great part of the wall then remaining, which has since been stubbed down. In 1773, stopping again at Chesterford, I had an opportunity of scrutinizing into the materials of the first foundation, which was a red sandy loom, intermixed with small stones, full 2 feet in heighth, on which was raised the more solid foundation, composed of rag stones and strong cement; this was full 3 feet in heighth, the top of which is almost equal with the present surface of the ground; and on this was built the wall, composed of rubble, stone, and cement, together with layers of bricks as above described. This station must have been very large, it is upwards of 1000 feet in length, and the breadth of the wall is a full 12 feet thick.
“The standard measure of the Roman brick, is 1 foot and a ½ in length, and 1 foot in breadth, according to Vitruvius: “But (continues Dr Woodward) in measuring some of these very exactly, I have found them 17 inches 4-10ths in length, and 11 inches 6-10ths in breadth, and 1 inch 3-10ths in thickness of our measure.” And this measurement exactly tallies with that which I made of those bricks from the old wall at Chesterford.”
Reference: See Dr Woodward’s Letter to Sir C Wren, published by Hearne at the end of the 8th vol. of Leland’s Itinerary.