Maker and Role
C. F. Casella and Co, Manufacturer
Altimeter, an aeronautical instrument showing height above sea level. There is a round dial with a white face. The numbers run anti-clockwise around the dial. The numbers run from 0 to 10 with 10 divisions between each number. Each number is 1000 feet and each division is 100 feet of altitude. The instrument is housed in a circular, grey, metal casing. There are 4 brass screws on the back of the instrument securing the works. Located on the flange surrounding the glass face cover is a metal knob, 20 mm in diameter. This knob has a corrugated edge. By twisting the knob, the hands on the dial can be set at sea level before the flight commences. An arrow is set from the centre of the dial with a blue arrow hand pointing in one direction and the back of the arrow extends backwards from the centre point. The back of the arrow has 2 metal tail feathers. The end portion of the arrow is silver. On the back of the casing is engraved W ^ D.
Signature/Marks and Type
Mark IV A/ No. 2217 G/ casella/ London Maker's Mark
W D Engraved
C. F. Casella and Co. Altimeter, 2003.609. The Museum of Transport and Technology (MOTAT).