The Geophysical Laboratory Temperature Scale

It is of interest to Earth scientists that one of the most prestigious laboratories in the field of experimental petrology and geochemistry, the Geophysical Laboratory of the Carnegie Institution of Washington, has its own practical temperature scale. This was developed in 1914 by Arthur L. Day, based on earlier measurements with a gas thermometer by Day and Sosman, and these same fixed points have been used at the 

Geophysical Laboratory ever since, in spite of continual changes in the International Practical Temperature Scale (in 1927, 1948, 1969). As a result, experimental results from the Geophysical Lab over the years have a consistent base, and can be easily intercompared. Differences between the Geophysical Laboratory Scale and the IPTS are now all less than 1°C. 

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