1851 Great Exhibition: Official Catalogue: Class X.: Alex Gerard
109. GERARD, ALEX., Gordon's Hospital, Aberdeen — Inventor.
"Spherical- trigonometer," or an instrument adapted to the mechanical solution of problems in spherical trigonometry and nautical astronomy.
Portable, or field transit instrument, for finding the time on shore, laying down meridian lines, etc.
Water-meter, for registering the quantity without interrupting the pressure.
Clock, with conical pendulum.
Marine clock, with two pendulums.
A centrifugal, or conical pendulum clock; capable of performing much heavy work with great accuracy.