Baird & Tatlock Revolving Mirror Apparatus,
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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  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.
