Baird & Tatlock Revolving Mirror Apparatus,
An Antique Baird & Tatlock Revolving Mirror Apparatus. This apparatus consists of a metal arm with stand, mirrored square box & geared cranking to rotate the mirror box.
The metal arm has a label imprinted “Baird & Tatlock (London), Ltd BLT, Gross Street – Hatton Garden – London EC”. It is probably from early 1900 to 1920s. The square wooden box has an original Â mirror on all four sides, with bevel gear to rotate the mirror box.
They used the rotating mirror to see the difference in two different frequencies with a manometric flame. For explanation see websitepage http://www.erittenhouse.org/articles/vol-26-contents-and-authors/the-manometric-flame/. Â The gear works perfectly and the box rotation is absolutely smooth. 48 cm High and dimension of the mirrors are 14 x 14 cm.