A rare Swiss electroplated aneroid pocket barometer compendium with altimeter, thermometer and compass, the register inscribed for E. Benzoni, Geneva, late 19th century The circular fired white enamel register with outer scale calibrated 34 to 80 for barometric pressure divided into tenths, the inner scale calibrated in reverse to 0-5,000 for altitude in feet and the centre signed E. BENZONI, GENEVE, in cylindrical plated brass case incorporating gilt on oxidised brass dial engraved with central compass rose with steel needle within raised silvered ring engraved in degrees calibrated 0 to 360 with every degree annotated, the outer margin with curved mercury tube CENTIGRADE thermometer set behing shallow convex glass with compass needle locking lever to circumference, the case with suspension ring to top and measuring 5cm (2ins) approx.; in original blue velvet and silk lined leather covered case. E. Benzoni of Geneva does not appear to be recorded in the usual sources however the inscription may well be that of the retailer of the current lot rather than the actual maker. The calibration for altitude being in reverse is highly unusual as is the barometric scale which to the best of the cataloguers knowledge does not appear to conform to any of the multitude of conventional units used for barometric pressure.