WWII era BRITISH G.P.O. BAROMETER & CASE with unique rotating bezel

Description

VINTAGE
1930's  to  1940's
G.P.O.
BRITISH  GENERAL  POST  OFFICE
GOV'T  ISSUED
COMPENSATED  BAROMETER
with  ROTATING  TOP  GLASS (Bezel)  &  INDICATOR
MEASUREMENTS:
Heavy Duty Box ...  3 1/2"  by  3 1/2"  by  1 1/8"
Barometer Diameter  ... 2 3/8"
Pictured and offered for sale is a 1930's to early 1940's G.P.O.  General Post Office,  British Government issued,  Compensated Barometer.
GOV"T  MODEL  FEATURE  is that the top half rotates for the purpose of setting the indicator  (currently can be seen at the 29.1 dial mark ) to monitor any small rising or declining of pressure.  The glass and brass top ( gripping in brass ) with stationary
indicator,  can be rotated to place indicator over barometers indicator hand allowing the user to monitor what direction the pressure is moving.
Original Formed Box is heavy duty construction, made for daily handling and housing the barometer,  excellent condition.  Clasp operates as it should, firmly.
CONDITION :  Dial face is in excellent condition, no defects.   Box in excellent condition, no defects.   Brass barometer no corrosion, no defects.  Bevel edge glass is clear, no defects.  If the barometer is removed from its case, sat on a surface, there exists scratches on backside from doing this.  Nothing major,  superficial only.  Barometer operates as it should.  Instructions are all over internet to set up a compensated barometer in your area of use.  Setting screw, backside,
within hole.