An early Twentieth Century Negretti & Zambra Pocket Weather Forecaster.
Patented by the firm in 1915 (Patent No: 6276/15) this handy small scale forecaster proved extremely popular during the period. Using the direction of the wind and barometer reading it became possible for the user to be able to forecast changes in the weather for the coming 12 hours. Variations in readings can also be set to allow for seasons or time of year.
This example is in fine condition with its original faux snakeskin card box and instructions still affixed to the inside of the lid.