General Information

Serial #

N/A

Part Number

1

Total Parts

2

AKA

N/A

Patents

N/A

General Description

.1 WOOD CASE WITH LEATHER HANDLE & METAL HARDWARE; METAL RHEOSTAT WITH SYNTHETIC PARTS; METAL METER CASING WITH GLASS DIAL COVER, SYNTHETIC PARTS/.2 METAL JACKS & WIRING, SYNTHETIC WIRE COVERING/ 2 UNIDENTIFIED PARTS: PLASTIC CASINGS, METAL WIRING, FIBRE CORD

Dimensions

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

Length

52.0 cm

Width

43.5 cm

Height

18.5 cm

Thickness

N/A

Weight

N/A

Diameter

N/A

Volume

N/A

Lexicon

Group

Meteorology

Category

Atmospheric humidity measurement

Sub-Category

N/A

Manufacturer

AKA

PNFI

Country

Canada

State/Province

Ontario

City

Chalk River

Context

Country

Canada

State/Province

Ontario

Period

1930'S

Canada

INSTRUMENT BUILT BY MEMBERS OF CANADIAN FORESTRY SERVICE./ FROM COLLECTION OF FORESTRY & FIRE-FIGHTING EQUIPMENT USED BY & ACQUIRED FROM PNFI, CANADIAN GOV'T FORESTRY-RESEARCH ESTABLISHMENT WHICH OPERATED FROM 1918-1995. PNFI STUDIED SPECIES GROWTH & FOREST MANAGEMENT, PARTICULARLY FIRE PREVENTION & SUPPRESSION.

Function

INSTRUMENT USED TO MEASURE MOISTURE CONTENT IN TOP LAYER OF FUEL ON FOREST FLOOR IN ORDER TO ESTIMATE DANGER OF FOREST FIRE, PROBABLY USED EXPERIMENTALLY IN DEVELOPING FOREST FIRE DANGER RATING SYSTEM IN 1930'S. (.2 WAS SENSOR USED FOR SOIL MOISTURE MEASUREMENT - SEE SUPP. INFO.)

Technical

ONE-OF-A-KIND OR ONE-OF-A-FEW SPECIALISED INSTRUMENTS MADE BY PNFI, PROBABLY BY JAMES G. WRIGHT OF PNFI, UNDER WHOM RESEARCH INTO FIRE CONTROL BEGAN IN 1929. ADAPTATION OF LIMBRICK MOISTURE METER DEVELOPED BY CHARLES LIMBRICK, WHO WORKED FOR OTTAWA INSTRUMENT FIRM IN 1920'S. SENSOR WAS BLOCK OF PLASTER WITH TWO WIRES EMBEDDED WITHIN BY WHICH RESISTANCE WAS MEASURED.

Area Notes

Unknown

Details

Markings

DETACHED PLATE FROM RHEOSTAT READS "MADE IN U.S.A./ CENTRAL SCIENTIFIC CO./ AMP.25/ TRADE MARK CENCO REG. U.S. PAT. OFF./ 5890 OHM/ CENCO RHEOSTAT/ CHICAGO/ BOSTONTORONTO/ NEW YORK LOS ANGELES"/ LETTERING ON METERS FACES READS "PAT. NOV. 6,'88. APR. 29,'90. FEB. 17,'91. OCT. 4,'98. JULY 16,'01/ MILLIAMPERES D.C./ WESTON ELECTRICAL INSTRUMENT CORP., NEWARK, N.J.,U.S.A./ MODEL 301 NO. 857031"; "MILLIAMPERES D.C./ WESTON ELECTRICAL INSTRUMENT CORP., NEWARK, N.J., U.S.A./ MODEL 301 NO. 1023922"; VOLTS D.C./ 200/ OHMS PER VOLT/ WESTON ELECTRICAL INSTRUMENT CORP., NEWARK, N.J., U.S.A./ MODEL 301 NO. 1025114"/ LABELS ON 2 PARTS READ "MADE IN U.S.A./ M.C. STEWART/ ARLINGTON, MASS."

Missing

PLASTER SENSOR

Finish

UNFINISHED WOOD CASE/ BLACK PAINTED & METALLIC METAL PARTS/ COLOURLESS TRANSPARENT GLASS GREEN & BEIGE WIRE COVERING/ PARTS: BROWN PLASTIC CASINGS

Decoration

N/A