Scales for Apothecaries and Assayers

c. 1850 – c. 1950

Richard Paselk, Curator

Pharmacist’s Torsion "Box Scale"

These balances were used for general chemical and pharmaceutical work at intermediate sensitivity and capacity (±4 mg. & 120 g). In the torsion balance design the knife edges and plates are replaced by steel bands as fulcrums. Claimed advantages include the lack of bearing surfaces to degrade and wear, and the self damping character of the bands. The weights on display are not original to this scale but were typically used by pharmacists with scales of this vintage making up prescriptions.

Description

Case: 12”l x 6 1/4”h x 5 1/2”d made of cherry(?) with a white marble top and a glass plate in the cover. Visible metal parts are nickel plated brass with the exception of of the japanned cast iron base, as seen in the photograph of the balance with the lid open. Two leveling screws work against a single concealed leg. Balance is achieved by matching two moving needles in a window on the front center of the case. There is a partial arrest knob below the window. The original pans are missing (the pans in the photo are replacements from an "army prescription scale" - they are essentially identical to the pans on other torsion scales of this type). There is a nickel plated tag on the front of the case below the window: “The Springer Torsion Balance Co./ Style 271 New York No. 18923 / Pat. Jan. 6-85. Jan 22-89. May 19-91”. Click here to view pdf copies of the 1885 and 1891 patents.

*The Springer Torsion Balance Co. was first incorporated in 1897, changing its name in 1902 when it was incorporated as the Torsion Balance Co. The tags on early Torsion balances similar to the model on display have "Springer" removed, with the remaining information unchanged as seen in a photograph of a later label shown below from an ebay auction. The latest patent date on the tag and the change in company name thus date the scale on display to between 1891 and 1902.

© R. Paselk 2013, Last modified 31 December 2020