Bench Four · Glass, Lead, and Nothing Else

The Glazier's Wheel —
cut your own rose, then let the noon through

You will not get this wrong. A rose window is arithmetic wearing a party dress: pick a number, divide the circle by it, and hand the rest to the sun. Turn the wheels below and watch the floor take the color.

A rose window of cut glass in concentric rings of petals around a bright oculus Every pane is a wedge of colored glass held in dark lead. One pane, in the second ring, is the wrong color on purpose — the apprentice cut it that way in 1911 and three generations of glaziers have refused to replace it.

Four things the bench will teach you anyway

  1. Choose an even number and the window will forgive you everything else. Twelve is the old favorite because it divides by two, three, four and six, which means the tracery can change its mind halfway out and still land square.
  2. Ruby is not a color, it is a sandwich. Flashed ruby is a whisper of gold-struck glass rolled onto clear — a solid pot of it would come out of the kiln nearly black and let nothing through at all. Hold a sheet to the window and you can see the seam.
  3. Blue does the carrying. Put cobalt at the outside and it will haul the whole wheel toward you across forty feet of nave. Put it in the middle and the rose closes like a fist. Try it: slide the batch and watch the floor.
  4. The window is only half the work. The other half is the patch of light it throws, which walks the flagstones all day and is never in the same place twice, and which no one signs.

The batch on the bench

Cutting list, bench four: 1 oculus, rings as marked, all wedges to 6 mm heart lead, outer edge in 9 mm with a copper tie every third pane. Ruby flash struck with gold chloride at 0.018% by weight, annealed slow, four hours down. Cobalt from the old blue-house pot, batch 44, which everyone agrees is better than the new pot and no one can prove why. Vert-de-gris runs streaky and you should let it. The pane in the second ring that does not match — third from the vertical, sunwise — was cut by an apprentice named Mira Aulnay in the autumn of 1911, out of a sheet she had no business opening. She offered to redo it before the lead went in. The master said leave it, a wheel with no mistake in it is just a wheel. Every glazier since has priced a replacement and then, on some pretext, not ordered it.