Of Instruments
A cabinet of computing and measuring devices, drawn as plates in a manuscript, each one working.
Every instrument here turns a piece of mathematics into a motion of the hand: sliding, opening, laying rods side by side, tracing, or turning. Each folio has a few plates. Drag anything that looks like brass, read the result in the margin, and work the exercises under “Try this”; they tick themselves when you have done them.
Drawn for the Wending House, 2026.Into the house
¶How to read a folio
The plate. Each plate is one idea. The drawing is the instrument; its brass parts move, by mouse, by touch, or by the arrow keys once you have tabbed to them.
The margin. The reckoning at the top of the margin is written in as you work: the reading, and the reason for it. Below it, “Try this” sets small tasks in order of difficulty. The glosses, lettered a, b, c, explain the parts of the drawing; hover over one and its part is picked out.
The commentary. Below the plates: the mathematics in full, a little history, and where to read further.
The older cabinet. Some instruments have earlier, plainer editions, kept as they were, and there are more devices on the Puzzles & Devices page: the Slide Rule Cabinet, the Stereonet, Hamilton's Turns, the Tropical Slide Rule, and the p-adic Ruler.