Barothermograph having sylphon-driven pressure sensing movement, with polished cross shafts set on conical pivots, twin cross beams, the upper with fine adjustment knob. Original pressed and polished alloy ribbed recording arm with swinging gate mounting. Long nib. The thermal sensing movement mounted to the lower beam with helical bi-metallic sensor, counterweight and fine adjustment knob. Original pressed and polished alloy ribbed recording arm with swinging gate mounting, short nib.

All raised on four turned pillars over a short bevelled chassis bearing the maker’s particulars “Short & Mason, London, Made in England,” and serial “No A8366.” Arrestor bar with bell crank operation.

Standard pattern 3⅝” diameter recording drum, the dust cover bearing the number “38645,” seven day platform movement, captive key winding, self-adhesive papers. Lid.

The plinth with twin ink stations, frieze drawer, the glazed cover with heavy bevelled lights, those to the ends with air circulation apertures. Overall, polished lacquered finish.

A good instrument having been the subject of a comprehensive re-build including the drum clockwork movement. This particular barothermograph benefits from swinging gate recording arms: more expensive to make and imparting greater recording detail, a sign of quality. Both pressure and thermal sensing systems show good sensitivity and progression – see performance chart for pressure.

Some signs of re-finishing to brass work, minor marks and lubricant stains to cross beams, the original recording arms with minor points of distortion and rippling. Both nibs replaced.

The mahogany case with some spotted losses to lacquer, though it should be pointed out that most of this finish remains and retains much of its original colour.

The ink bottles are generic types with threaded tops evident, the dippers are correct.

Overall, this is a very good example of a barothermograph with a high level of originality, fully re-built to exacting standards, and correctly set up and tested under laboratory conditions.

Dimensions: 14½” wide x 9″ high x 9″ deep

Stock No: BG1128

Price: Vavasseur Archive