Accession No
1555
Brief Description
air meter, by L. Casella, English, 1860-1901
Origin
England; London
Maker
L. Casella
Class
physics
Earliest Date
1860
Latest Date
1901
Inscription Date
Material
metal (brass; aluminium); stone (mica); glass; wood; paper
Dimensions
box length 104mm; breadth 96mm; height 87mm
Special Collection
Provenance
Inscription
‘L CASELLA
MAKER TO THE ADMIRALTY & ORDNANCE
LONDON
AIR METER No 537’ (on dial)
‘Correction for Air Meter No 537 ...’ (in box)
Description Notes
Air meter for measuring air speeds in tunnels, buildings etc.
Brass cylinder with oblique aluminium-bladed fan mounted vertically on side of horizontal glazed dial. Axis from fan drives dial graduated 0 - 100 feet, numbered by 20, divide to 1; with five subsidiary dials graduated 0 - 10 by 1 for Hundreds, Thousands, 10 Thousands, 100 Thousands and millions feet per minute. Switch on side of dial. Dial mounted on turned brass feet on brass base with a hole for a screw in the middle.
Fitted wooden box. Paper label in lid.
Condition: fair; complete.
References
Events
Description
This instrument measures air flow or ventilation in buildings, flues and tunnels. A current of air causes the aluminium fan to rotate, the revolutions of its axis driving the counters on the dial face. The number of revolutions in a given time are then converted to give the air speed.
These instruments were often used in mining to check the ventilation of shafts.
This example was manufactured by the London instrument firm of Casella, around 1900.
26/03/2008
Created by: Dr. Anita McConnell on 26/03/2008
FM:43443
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