General Information

Serial #

N/A

Part Number

1

Total Parts

14

AKA

U-TUBE

Patents

N/A

General Description

STAINLESS STEEL

Dimensions

Note: These reflect the general size for storage and are not necessarily representative of the object's true dimensions.

Length

N/A

Width

N/A

Height

N/A

Thickness

N/A

Weight

N/A

Diameter

N/A

Volume

N/A

Lexicon

Group

Meteorology

Category

Atmospheric pressure measurement

Sub-Category

N/A

Manufacturer

AKA

MSC

Country

Canada

State/Province

Unknown

City

Unknown

Context

Country

Canada

State/Province

Ontario

Period

LATE 1950'S UNTIL AT LEAST C. 1970

Canada

CANADIAN DESIGNED & BUILT STANDARD BAROMETER USED AS CANADIAN PRIMARY STANDARD BAROMETER BY METEOROLOGICAL SERVICE OF CANADA.

Function

A SPECIALLY CONSTRUCTED INSTRUMENT THAT MEASURED ATMOSPHERIC PRESSURE & WAS USED AS CANADA'S PRIMARY BAROMETER, THAT IS, THE BAROMETER BY WHICH OTHERS ARE CALIBRATED (1).

Technical

U-TUBE BAROMETER DESIGNED BY BINDEN & VOCKEROTH AS MSC PRIMARY BAROMETER; IT HAD INVAR PROBES (WITH STEEL POINTS, GRATICULES, & REFECTING PRISMS) PROJECTING INTO TUBES, LIGHTS ON ENDS OF SEPARATE RODS, SCALES OBSERVED BY TELESCOPES, & HAD AN ACCURACY OF 20 MICRONS (REF. 1). THE BAROMETER CONSISTED ESSENTIALLY OF A STAINLESS STEEL U-TUBE OF 3 INCH I.D. THE TOPS OF THE ARMS OF THE U-TUBES WERE CAPPED AND THE HEIGHT DIFFERENCE OF THE FREE MERCURY SURFACES ON THE HIGH VACUUM ARM AND THE TEST PRESSURE ARM ARE WAS MEASURED DIRECTLY BY INVAR PROBES WHICH WERE INTRODUCED VERTICALLY INTO THE ARMS BY O-RING SEALS. PROVISION WAS MADE FOR TO OBSERVE THE COINCIDENCE OF THE MERCURY POINTS ON THE MERCURY SURFACE VISUALLY. THE DECISION ON THE EXACT SETTING OF THE POINTS ON THE SURFACE WAS MADE BY OBSERVING THE DISTORTION OF THE REFLECTION OF A GRID OF STRAIGHT LINES CAUSED BY THE DEFORMATION OF THE MERCURY SURFACE ON THE ENTRY OF THE PROBE POINT. THE PROBE ARMS WERE GRADUATED IN MILLIMETRES & THE HEIGHT DIFFERENCE BETWEEN THE FREE SURFACES OF THE MERCURY WAS MEASURED BY MEANS OF TWO MICROMETER TELESCOPES FIXED ON A STEEL PILLAR. THE ZERO DIFFERENCE BETWEEN THE POINTS WASW ESTABLISHED BY ALLOWING THE TWO FREE MERCURY SURFACES TO FORM A LEVEL SURFACE BY EQUALIZING THE PRESSURE IN BOTH ARMS. THE MEAN TEMPERATURE OF THE MERCURY COLUMN WAS ESTIMATED BY A SERIES OF 10 TEMPERATURE PROBES SPOTTED AT EQUAL INTERVALS THROUGHOUT THE MERCURY COLUMN. IT WAS ESTIMATED THAT THE PRESSURE COULD BE DETERMINED TO AN ACCURACY OF 20 MICRONS IN THE ROUTINE USE OF THIS STANDARD. (REF. 2).

Area Notes

Unknown

Details

Markings

NONE

Missing

LATHE BEDS, OTHER PARTS From CA of 11/03/1993 by Tony Missio: Undetermined According to MSC meteorologist (Oct. 2007), this artifact comprises only a portion of the original barometer and is missing a good part of its ancillary contstruction.

Finish

STAINLESS STEEL

Decoration

N/A