Current location:
Collection Storage Facility
Provenance:
This balance was used by the Institute for National Measurement Standards at the National Research Council (NRC) in Ottawa, Ontario, from 1938 to 1997. It may have been made by A. Rueprecht & Sohn of Vienna, Austria.
Technical history:
NRC scientists used this unique apparatus to meet stringent requirements of modern mass determinations. The balance was capable of measuring kilograms with precision greater than 0.02 to 0.03 mg. This was achieved by automating the process of moving masses and weights, using lasers to read and graph measurements, and maximizing advances in computer control.
History:
From 1938 until it was decommissioned in 1997, this was Canada’s primary balance used to make kilogram mass comparisons. It was, therefore, the most important piece of equipment for mass measurement in Canada; for almost 60 years, all mass standards were compared to results achieved with this instrument.
This photo shows the first major modifications to the balance. They consisted of a hydraulic method for loading the weights and a method to exchange the positions of two weights.
This photo shows the continuation of modifications that was done in the mid-1960’s. These modifications included a new method for loading the rider weights as well as a clamping arrangement to hold the balance pans
The balance in the Museum’s collection is the final version. Lorne Munro began working on it in 1982 and completed his modifications to the balance in 1989.
This photo shows Dr. George Chapman and the NRC primary balance used to make kilogram mass comparisons. Chapman was the head (1990s - early 2000s) of the Institute for National Measurement Standards, Canada's national metrology institute for evaluating methods of measurement.
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