BRIDOL is the British Sundial Society's Register of Fixed and Mass Dials, which gives detail and photographs of about 8000 fixed sundials and 3000 mass dials in the UK.
Some of these are in private gardens, but the majority are publicly available.
Installed by the conservatory in the rose garden is this heliochronometer by Pilkington and Gibbs of Preston, serial number 932. These instruments were made around the beginning of the 20th century to enable clocks to be accurately set by the sun. They required the user to set the current date on a calendar scale and this caused a cam inside the device to move one of the sighting vanes so that it made a correction for the Equation of Time. The sighting vanes could then be aligned with the sun and the time in GMT read very accurately from the hour scale. Sun time had been converted to clock time.
[This dial replaces a previous P&G helio-chronometer at this address, inscribed ’ROSS LIMITED 111 NEW BOND STREET LONDON W’, serial number 687, which was stolen.]
