About this site

MUJCA is an editorial site about how time got measured, and about the engineering that made the measurement trustworthy.

The letters MUJCA are the site’s name and nothing else — they do not stand for an organisation, a group or a membership body. What the site is, is nineteen written entries across six sections, each one taking a single piece of mechanism and naming the error it was built to defeat: recoil, friction, the effect of heat on a metal rod, the disturbance of the impulse itself, and finally mechanical resonance altogether.

The material is horological and historical. Makers, instruments and institutions are named where the record supports it — John Harrison, George Graham, Thomas Mudge, John Arnold, Thomas Earnshaw, W. H. Shortt, the Royal Observatory Greenwich, the Board of Longitude papers held at Cambridge, the Worshipful Company of Clockmakers. Where a story is traditional rather than documented, the entry says so rather than repeating it as fact.

The site sells nothing. There are no valuations, no auction results, no recommendations to buy, and no investment framing anywhere on it.

Photographs of mechanism are shown at close range because the argument usually lives in something small: a locking face, a pallet jewel, the wear on an impulse face.