Paper Machines

Instruments that readers turned, made to turn again

Before print, and long after, some books were built to be worked as well as read: circles that turned on a pin, arms that pointed, windows that showed the moon's phase. This exhibition rebuilds them as working instruments, from the manuscripts and printed pages that carry them, and keeps the reader's own effort in view: what the machine supplies, what the user must know, and what it cannot tell.

Figure T of the Ars brevis, redrawn: three coloured triangles inside rings of letters

Ramon Llull, The Art of Finding

Ars brevis, 1308

Four figures and a turning wheel, redrawn after the manuscripts

Turn the three circles of the Fourth Figure, read the letters through the alphabet's six columns, follow Llull's own argument through the chamber BCD, and read all 139 questions of the Ars brevis in Latin and English.

Open the machine →
The moon disc of the volvelle in MS. Ashmole 370, cut from the photograph

Nicholas of Lynn, The moon, the hours and the tides

Kalendarium, 1386; Bodleian MS. Ashmole 370, c. 1424

The manuscript's own volvelle, photographed and made to turn

Two discs on a pin in the Bodleian's photograph: set the sun's pointer to the day, the moon's pointer to the moon's age, and read the hour, the bearing and the phase, as the sailors of Lynn did.

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The Instrumentum veri motus lunae of the 1476 Kalendarium: a zodiac ring, an inner ring numbered one to six, two paper wheels and a sun with a rosette at the centre

Regiomontanus, The true place of the moon

Kalendarium, Venice 1476

The printed book's own volvelle, photographed and made to turn

Two paper wheels and a thread in the Smithsonian's copy of the first printed calendar with instruments: set the wheels to the year's roots, count the day's lunar numbers from their heads, and read the moon's mean place on the zodiac and its correction on the ring Regiomontanus called the moon's equator.

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A line of numbers with the opening words of the psalms written beneath them, in the manner of Hugh's memory lesson

Hugh of Saint Victor, Addressable memory

Chronicle, c. 1130

A machine made of numbers, words and the reader's mind

Learn Hugh's line of numbers the way he taught it to his students, with the psalms' opening words hung on it; then have the words taken away, and the line, and see whether you can still reach any number directly, in either direction.

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A ruled page of Hugh's Chronicle: six columns of years, indictions, popes and emperors, one row of them marked

Hugh of Saint Victor, The line of years

Chronicle, c. 1130

Persons, places and times on one line, photographed and made to run

One row for every year from the Incarnation to Hugh's own day. Move the pointer along the photographed leaves and read off who held the see of Rome and the Empire, how far into each reign the year stands, and where Hugh's dates part from ours.

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The plan of Noah's ark drawn from above: a long rectangle with a small squared cubit at its centre, a line of names running its length and an oval of the world around it

Hugh of Saint Victor III — Construct the Ark

Libellus de formatione arche, c. 1128

A lost painting's instructions, executed one sentence at a time

Hugh's text is not a description of a picture but the orders for drawing one, and the picture is lost. Read each passage and apply it: the drawing grows by exactly what those words warrant, and every line says whether Hugh states it, whether we infer it, or whether we had to choose.

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Next on the bench

Candidates under consideration

The great wheels of Apian's Astronomicum Caesareum (1540); a sister copy of Nicholas of Lynn's Kalendarium; Harsdörffer's five-ring word wheel (1651); the tide almanac of Brouscon (1546); the eclipse wheel of Sacrobosco's De sphaera. Each will come with its sources and its limits stated.

How these machines are made

Where a manuscript's own instrument survives, as with Nicholas of Lynn's volvelle, the machine is the photograph itself: the moving parts are cut along their outlines and pivot on the pin, and anything the page cannot show is reconstructed in the open and can be switched off. Where the design is transmitted in many copies, as with Llull's figures, it is redrawn after the manuscripts and the early prints. Every page names its sources, states its rights, and separates what the historical author wrote from what the exhibition supplies.