General Information

Serial #

N/A

Part Number

1

Total Parts

3

AKA

Westphal or Mohr balance

Patents

N/A

General Description

ALL BRASS CONSTRUCTION, SAVE SYNTHETIC (FRENCH IVORY?) SCALE..3 PAN PROBABLY ALUMINUM; COPPER WIRES. WOODEN BOX LINED WITH GREEN FELT PADS; FITTED WITH BRASS HINGES, CLASP & CORNER REINFORCEMENTS

Dimensions

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

Length

14.5 cm

Width

7.5 cm

Height

20.3 cm

Thickness

N/A

Weight

N/A

Diameter

N/A

Volume

N/A

Lexicon

Group

Metrology

Category

Mass/weight

Sub-Category

N/A

Manufacturer

AKA

Unknown

Country

Unknown

State/Province

Unknown

City

Unknown

Context

Country

Canada

State/Province

Unknown

Period

THIS SCALE PROBABLY USED C.1875-1930S, AND POSSIBLY LATER

Canada

ONE OF A NUMBER OF ITEMS RECEIVED FROM GEODETIC SURVEY DIV., DOMINION OBSERVATORY OTTAWA. THESE INSTRUMENTS WERE USED BY DOMINION OBSERVATORY STAFF IN THE COURSE OF GRAVITY SURVEYS CONDUCTED BETWEEN C.1902-1970S.

Function

USED TO MEASURE THE RELATIVE DENSITY OF ROCK AND/OR MINERAL SPECIMENS AND/OR LIQUIDS. Westphal's (or Mohr's) Balance is used to measure the specific gravity (or density) of liquids. Method of use (courtesy of Dr. Tom Greenslade, Kenyon College. The arm is first balanced with the plummet totally immersed in water at 15.5 degrees C. The plummet has a built-in thermometer and has a known volume (equal to 5 gms of water at 15.5 degrees C) and mass (15 gm). A 5 gm mass is placed on the hook holding the plummet, and the screw on the foot is adjusted until the index pointer on the end of the beam lines up with the point on the frame. The plummet is then completely immersed in the unknown liquid, and the system is rebalanced, using a series of riders on the nine equally paced notches on the beam, thus giving the value of the added mass for each decimal place. This gives the buoyant force of the liquid relative to water, and hence the specific gravity, which may be obtained to four decimal places.

Technical

EXAMPLE OF WESTPHAL - TYPE BALANCE USED FOR MEASURING THE RELATIVE DENSITY OF ROCK AND/OR MINERAL SPECIMENS BY SUSPENDING THEM FROM THE BALANCE BEAM INTO A LIQUID OF KNOWN DENSITY.

Area Notes

Unknown

Details

Markings

SCALE (SPECIFIC GRAVITY?) DIVIDED 0-9 AND MARKED AT .5 INTERVALS ON BALANCE ARM

Missing

PROBABLY MISSING ORIGINAL PAN

Finish

BRASS HAS BEEN LACQUERED ON .1-.2. READING SCALE ON .1 ETCHED IN BLACK ON WHITE PLATE. PIVOT BAR AND READING INDICATOR ON .2 ARE SILVER METAL (POSSIBLY GERMAN SILVER). .3 PAN HAS BLACK FINISH APPLIED TO UNDERSIDE.

Decoration

NONE