The Ramsden workshop and the production of the Palermo circle

Anita McConnell

Jesse Ramsden (1735-1800) was London's leading maker of astronomical instruments at a time when many observatories were eqiuipping themselves with new and larger apparatus. But scaling-up designs presented the maker with many problems: obtaining brass in adequate dimension, constructing limbs with combined strength with lightness, and finding the right metal for bearings, all of which led to novel instruments. A capacious workshop was necessary to erect and test such apparatus.
Ramsden had the space and the skilled workforce, but business often took him away from London; all these matters perhaps explain the delay in completing Piazzi's great circle.