Humboldt State University ® Department of Chemistry
Robert A. Paselk Scientific Instrument Museum
Specific Gravity Balance, Chainomatic
Humboldt College, 19591
The chainweight balance allowed more rapid determination of small weights by substituting a precision chain weight for the small weights of the traditional balance. This balance determines specific gravity of liquids quickly and precisely. The rider and Chainomatic dial read specific gravity directly from 0.0000 to 2.0000. The plummet/thermometer displaces exactly two grams of distilled water 20°C. The built-in thermometer allows corrections to be made if the sample is not at exactly 20° C. The pedestal for the sample cylinder slides away revealing a hole in the base-plate of the case. This allows the hydrometer cylinder to be lowered and tilted for easy removal or insertion without disturbing the plummet. The catalog description is from the Van Waters and Rogers (San Francisco, 1968) Catalog 69 Scientific Apparatus instruments and supplies for: Industrial, Educational, Clinical and Research Laboratories.
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.
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. The case is 20"h x 18 1/4"w x 9"d. The balance includes a two gram plummet, calibrated at 20° C, shown in the close-up digital image, with a built-in thermometer with a range of 10°-30° C. There is also a ungraduated glass cylinder, as seen in the close-up image. A small cardboard box (3 5/8" x 2 5/8" x 7/8") originally containing the chains for this balance was found in the balance drawer.
See catalog description for additional details. (Property tag: State of California/ 43910) More information on this and other balances is available on the Chemical Balance at Humboldt pages accessed via the link below.
1 According to the equipment inventory list for HSU this balance was acquired in 1959.