Early Twentieth Century Max Min Thermometer by Negretti & Zambra

For sale an early Twentieth Century max min thermometer by Negretti & Zambra of London.

Comprised of a white painted and cast metal scale, manufactured in relief so that the scale and body detail is raised from the body of the instrument. It has ascending and descending Fahrenheit scales measuring -10 to 120 degrees with company name below and logo to in between the thermometer.

Evidently designed for external use due to the materials involved and the roof shaped cover at the top of the instrument, Negretti advertised these thermometers as follows:

“This thermometer registers the greatest cold, the greatest heat, and the present temperature. It is an ideal thermometer for the greenhouse, garden and general outdoor use”.

The max min thermometer is a simple but effective instrument whereby two metal pins are inserted into the bore of the thermometer tube. With the use of a weak magnet, the pins can be guided to rest on the top of the thermometer liquid level and will therefore move with the liquid in accordance with the change in temperature. Once the liquid recedes with a drop (or increase - e.g max min) in temperature, the metal pin will remain at that farthest position allowing the observer to record the hghest and lowest points in temperature over a given period.

Not the rarest of Negretti & Zambra’s catalogued instruments but unlike many other examples, this one seems to have had a somewhat easier life and retains nearly all of its original paint and a functioning thermometer tube. It remains a very useful and functional instrument.

Negretti & Zambra were a leading name in the production of meteorological and scientific instruments and had a company history dating back to 1850 although their parents were amongst those Italian emigres that bolstered the British meteorological instrument making industry at the turn of the century.

Throughout their long and esteemed history they exhibited at British and international industrial fairs and became makers to both Queen Victoria and Edward VII. Owing to changes in the business, the firm ceased the public retailing of scientific instruments sometime around the late 1960’s and continued with a focus on the aviation industry in numerous guises until its eventual liquidation in the year 2000. They are today perhaps the most collected of the scientific instrument firms which bears testament to the quality of their work.

Circa 1920