The High Scaffold Correspondence

• Chapter 1 The Foundation Line
• Chapter 2 The Quarries of Saint-Jude
• Chapter 3 The First Course of Ashlar
• Chapter 4 On the Mix of Quicklime
• Chapter 5 The Geometry of the Transept
• Chapter 6 Sand from the Riverbank
• Chapter 7 The First Weight-Bearing Arch
• Chapter 8 Letters to the Master of Works
• Chapter 9 The Plummet and the Square
• Chapter 10 A Defect in the Flying Buttress
• Chapter 11 The Bishop’s Ledger
• Chapter 12 Wintering Beneath the Canvas
• Chapter 13 Calculations at One Hundred Feet
• Chapter 14 The Guild of Scaffolders
• Chapter 15 Cracks in the Mortar Bed
• Chapter 16 The Treadwheel Crane
• Chapter 17 The Wind from the North
• Chapter 18 An Error in the Radius
• Chapter 19 The Second Tier
• Chapter 20 The Leaning Pillar
• Chapter 21 Iron Cramps and Lead
• Chapter 22 Three Hundred Feet Above the Earth
• Chapter 23 The Mason’s Mark
• Chapter 24 The Storm of Saint Michael
• Chapter 25 The Final Keystone
• Chapter 26 The Height of the Tower

Letter from Master Mason Jonas of Bury to Brother Thomas, Master of the Fabrics at the Abbey of Saint-Jude-in-the-Fens. Dated the fourth day after the Feast of Saint Barnabas, Anno Domini 1372.

To the venerable and devout Brother Thomas, keeper of the accounts and guardian of the stone, Master Jonas sends greeting.

I arrived at the site three hours after noon, having been delayed by the state of the lower causeway, which has drowned under two feet of black river mire since the spring rains. My horse, a beast of small patience and less intellect, refused the ditch near the third boundary stone, forcing me to haul my own chest of instruments the remaining mile on foot. I recount this not to solicit your pity, Brother, but to explain why the ink on this

Letter from Master Jonas of Bury to Brother Thomas, Master of the Fabrics. Sent from the Upper Pit at Saint-Jude’s Ridge, the ninth day after the Feast of Saint Barnabas, Anno Domini 1372.

To Brother Thomas, whose patience I must again test before a single stone is set upon another.

I am writing this from a wet wooden shed at the edge of the lower quarry wall, with the sound of steel picks ringing off the cliff face below me so loudly that my ears hum like church bells. I have spent the last three days wading through the strata of Saint-Jude’s Ridge, and I must report that the stone we were promised by the bailiff is not the stone we have been given by Almighty God.

The top layer—what the local quarrymen call the bask-stone—is a yellow, crumbly freestone that crumbles between a man’s fingers if he squeezes it with any vigour. It is light enough to haul without breaking a oxen’s neck, which no doubt explains why the bailiff’s men were so eager to stack forty tons of it beside the river landing. If we lay this yellow junk into the foundations of a tower intended to reach four hundred feet, the entire structure will dissolve into fine flour the first time a severe frost takes hold of the mortar joints. I have rejected the entire upper bed, to the great distress of Master Giles the quarry-reeve, who threatened to appeal directly to the Lord Abbot. I told him he might appeal to the Pope if it pleases him, but his holiness will not be standing beneath four thousand tons of collapsing masonry when the base gives way.

Below the yellow bed lies the true limestone: a cold, blue-grey shelf of close-grained rock that rings like iron when struck with a hand-hammer. This is the heart-stone we require. It is dense, heavy, and reluctant to yield to the chisel, but it will bear the weight of the heavens if we set it upon its natural bed.

However, we face three immediate difficulties with this lower bed.

First, the seam lies twelve feet below the water table of the upper marsh. Even now, six laborers are working a pair of wooden chain-pumps day and night merely to keep the quarry floor from turning into a fishpond. If the pumps stop for two hours, the working face is drowned.

Second, the stone is stratified in irregular courses. To obtain a block four feet long, two feet wide, and eighteen inches deep—which must be our standard size for the outer skin of the tower base—we must quarry away nearly twice that volume in shattered shingle and soft marl. The waste heap is already higher than the quarry tree line.

Third, there is the matter of the transport. The blue limestone is so dense that a single cubic foot weighs upwards of one hundred and sixty pounds. A standard block of eight cubic feet will therefore weigh upwards of twelve hundredweight, excluding the timber sled and iron bindings. The wooden wagons provided by the abbey tenants are cracking their axles before they reach the main trackway.

I include below my rough reckoning of the stone required for the first tier alone, so that you may adjust your ledgers and inform the kitchen master that we shall need forty more men at the picks if we are to clear the site before the autumn floods.

Extract from Master Jonas’s Pocket-Book of Calculations, bound in pigskin:

Letter from Master Jonas to Brother Thomas. Dated the Vigil of Saint John the Baptist, Anno Domini 1372.

Brother Thomas,

I have received your letter wherein you express alarm at the price per yard demanded by the quarrymen for the blue-grey stone. You ask whether we might not mix the soft yellow stone into the interior core of the wall to save both silver and oxen-flesh.

I must answer you with all the plainness of a man who has seen the south tower at Lincoln settle three inches to the west because of bad core-filling.

A stone wall is not merely a pile of rocks held together by wet sand. It is a living machine. The outer ashlar skin and the inner core must act as one single body against the down-thrust of the spire. If we place hard blue stone on the outside and soft yellow sand-stone on the inside, the soft stone will yield under the pressure while the hard stone stays rigid. The wall will then split down its middle like an old turnip, the outer skin peeling away from the heart and dropping into the churchyard.

If the abbey wishes to build a spire four hundred feet high—a height, I remind you, that no master mason in this diocese has ever dared attempt upon fen-land—we cannot afford cheap mercy to the stone. Every block that enters the foundations must be of the blue shelf, sound and free of dry-seams or iron-veins.

Yesterday we split a block seven feet long that promised to serve for the great eastern corner-buttress. It looked flawless on all six faces. But when Robin the carver struck it with his mallet to begin squaring the bed, the entire block parted along an unseen line of calcite as clean as if it had been sawn. The crack was filled with dry white powder—what the quarrymen call "throat-rot." Had that block gone into the third course beneath the turf, the entire eastern buttress would have sheared off within ten years.

I have instituted a test for all stone coming out of the lower pit. Every block, once split, must be washed clean of quarry-sap with river water and left exposed to the sun for forty-eight hours. Then, my boy Peter strikes each corner with a two-pound steel hammer. If the ring is clear and high, like a sanctus bell, we mark it with the tower mark—the three crossed calipers—and load it onto the sleds. If it sounds dull, like a struck cabbage, it is thrown into the lime-kiln pit to be burned into powder.

Master Giles screams that I am ruining him, and that the abbey will be bankrupt before we reach the water-table. I answered him that a bankrupt abbey is a regrettable thing, but an abbey buried under forty feet of fallen rubble is far more difficult to clear out for Matins.

Send more iron for the picks. The local blacksmith is using soft iron from the forge at Swaffham, which turns its edge after three strokes against the blue stone. I need Spanish iron, steel-faced, or we shall spend more time heating picks in the charcoal than we do quarrying.

Also, send two barrels of small beer for the pump-men. They are working knee-deep in cold spring water under a midsummer sun, and their tempers are as thin as the bailiff’s soup.

Note scribbled in the margin of the Quarry Account Roll by Brother Thomas:

Delivered to the upper pit: twelve bars of imported iron, four pounds of tallow for the axle-trees, and one barrel of small beer. The second barrel is withheld until Master Jonas delivers the draft for the lower footings.