A very nice example of Negretti & Zambra’s desk weather forecaster, dating from c.1920. This makes a perfect companion piece to a barometer or barograph, where the readings can be hard to interpret.
The cast aluminium case has an engraved and silvered brass fascia signed by the maker. It is also stamped with Patent 6276/15.
The forecasting dial is set according to barometer readings. It has an outer scale from 28 to 31 inches of mercury. The disc behind has alphabetical codes and a direction of wind index.
The side-mounted wind direction selector lever is then set.
Depending on the prevailing conditions of “Falling,” “Rising” or “Steady” pressure (again, as observed from the barometer / barograph), a letter-coded forecast is shown.
Turning the knurled setting wheel of the lower cylinder to reveal this letter code in the elongated aperture gives Negretti & Zambra’s forecast interpretation.