Humboldt State University ® Department of Chemistry

Robert A. Paselk Scientific Instrument Museum

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Analytical Balance, Chainomatic

Model AB-2 

Christian Becker

No 30803

Humboldt College, 1952

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Use/History

The chainweight balance allowed more rapid determination of small weights by substituting a precision chain weight for the small (<100 mg) weights of the traditional balance. Thus, once the operator came to within 100 mg of the desired weight, he/she would no longer need to arrest the beam, open the balance case, add additional weights, close the case, release the beam and observe its swing, etc. greatly speeding the determination of exact weights. This instrument also has a notched beam allowing up to 1 gm of additional mass (for a total of 1.1 gm) to be added without opening the case.

The chainweight balance was patented by Christian Becker in 1915.1 Christian Becker introduced aluminum cased balances such as the current model in 1950, replacing the older mahogany cased versions. This was the elite balance for the chemistry department when it was obtained. Mervin Hanson, a student in the Humboldt chemistry department (1956-1961), and later a Professor (1965­) commented that he was finally allowed to use this balance when he was a senior!

Early/contemporary descriptions of the features of the balance and its use are provided below:

Description

This is Christian Becker's top-of-the-line Chainomatic analytical balance. The aluminum case is gray crinkle finished with nickel plated (now corroded on the outside) trim. There are glass panels on the front and top, with a translucent opal glass panel on the back. The plate is black glass setting on a cast aluminum base.l. The case is 20"h x 18 1/4"w x 9"d. There is a drawer in the base. The balance has stainless steel pans on polished brass, 3-piece, hangers. The column is enclosed in a polished brass sheath. See catalog descriptions for additional details. (Property tag: State of California/ 43910). As seen in the enlarged image, a nickel-plated black-painted brass tag attached to the back of the balance case provides the style (AB-2), capacity (200 g) and serial number (A 4731). A small cardboard box (3 5/8" x 2 5/8" x 1/2") originally containing the chain for this balance was found in the balance drawer. Original wrappings etc. were still in the box as shown in the image.

Research

According to the equipment inventory list for HSU this balance was acquired in 1952 for $462.48. This balance is described in the New Item Supplement (pg1554) of the 1950 Cenco Catalog (J150). Additional specifications are given in the description of the previous wood cased balance on pg 5 of the same catalog. Christian Becker was established in Jersey City, New Jersey in 1892, it later became a part of the the Torsion Balance Co, Clifton, N.J.2 A history of this company is available on-line.

References

1Stock, John T. Development of the Chemical Balance. Her Majesty's Stationary Office, London (1969), pg 30. "The 'chainomatic' principle, used earlier in other connections, but patented by Christian A. Becker (1874­1946) in 1915,..."
2MacNevin, William Marshall, The Analytical Balance, Its Care and Use. Handbook Publishers, Inc., Sandusky, Ohio, (1951), pg. x-xii.

The Chemical Balance at Humboldt

HSC 1936-53 Scientific Instruments

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HSTC (1921-34)
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HSC (1935-1953)
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HSC (1954-1973)

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© R. Paselk

Last modified 22 September 2013

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