Metallic thermometer having 8” vitreous enamel printed dial calibrated in degrees Fahrenheit with a range from 0 – 110, with ten degree stations and divided to single degrees, annotated “Freezing,” “Temperate,” “Summer Heat” and “Blood Heat,” fine blued steel pointer, all set beneath a bevelled glass maintained in a brass bezel with highly polished reflector ring. Upper portion marked “Patent Metallic Thermometer” and serial “No 1383.”

The movement, constructed in brass, comprising twin bi-metallic strips acting in opposition upon a rack about a common shaft, and marked “Pat. Apr 12, 1881.” The arbour with pinion drive.

All contained within a turned and decorated oak polished case, the verso with removable circular panel, hanger to top.

Unusual, certainly attractive and of particular interest regarding the mechanism, the patent of William Atherton Wales of  Newton, Massachusetts, April 12th 1881. Wales’ patent sought to improve existing dial thermometers, many of the type patented by Seymour in February 28th 1860. The limitations of these thermometers are well explained in the William A. Wales US Patent Specification No. 240,059.

Extremely rare – despite extensive research, we have only found one other later example, dating probably to 1910 – and possibly the earliest existing example of its type. Certain characteristics of this instrument would suggest production by Negretti & Zambra built around an imported American movement. It is interesting to note that the case has been formed internally to accommodate the movement as illustrated in the patent which would suggest that the patented movement was refined whilst in production.

The case was designed for the patented movement as shown – the movement within it is clearly a refinement.

Stripped, cleaned and serviced, the brass movement simply patinated with age, this is a sensitive and accurate instrument. This is a real collector’s piece and an ideal companion to a wall barometer or clock.

NB: This is a mechanical device that does not contain mercury.

Dimensions: 11″ diameter x 2¾” deep

Stock No: SI0660

Price: SOLD