This thermometer is so designed that an air bubble separates a small amount of mercury from the main part of the column. When the instrument is mounted horizontally, the detached mercury remains in place when the rest of the column falls, thereby indicating the maximum temperature. John Phillips, an English geologist, introduced the form at the 1832 meeting of the British Association for the Advancement of Science. In 1856 he showed an improved form made by Louis P. Casella of London.
Appleton's Encyclopaedia noted in 1860 that James Green of New York "appears to have removed the objections to the previous forms of the maximum thermometers, and produced a highly simple and perfect instrument." Henry J. Green, who was James Green's nephew and successor, also made instruments of this sort. This example has a grooved aluminum plate that is marked "H. J. GREEN B'KLYN. N.Y." and "NO. 9746 U. S. WEATHER BUREAU" and "MAXIMUM." The plate is graduated every 5 degrees Fahrenheit from -20 to +125. The bulb is spherical. The stem is marked "U.S. 9746" and is graduated every degree F. from -22 to +126. It was made between 1890 (when H. J. Green moved his business to Brooklyn) and 1904 (when it came to the Smithsonian).
Ref.: Henry J. Green, Meteorological and Scientific Instruments (Brooklyn, 1900), p. 22.
Our collection database is a work in progress. We may update this record based on further research and review. Learn more about our approach to sharing our collection online.
If you would like to know how you can use content on this page, see the Smithsonian's Terms of Use. If you need to request an image for publication or other use, please visit Rights and Reproductions.