Kew Pattern Hygrometer
This is a high quality hygrometer using accurate stem-divided, mercury-filled thermometers which are made with consideration to BMO patterns. The thermometers are fitted to laminated plastic mounts which have been engraved with thermometer divisions. The mounts themselves are then fitted onto a laminated plastic back-plate, moulded from high strength, ‘warp-resistant’ plastic.
A metal bracket attached to the back plate, supports the water reservoir from which a cotton wick runs and is threaded around a circle of muslin covering the bulb of one of the thermometers. The bulb is kept constantly wet by capillary action.