NEGRETTI & ZAMBRA
This pocket forecaster was patented by Negretti & Zambra in 1915. It is a circular slide rule (diameter 55mm) that is used in conjunction with a barometer to predict the weather for the next 12 hours. I have tried it, and it really does work!
The forecaster is in mint condition. The box is in worn but complete condition. The instruction pamphlet is only one of the pages, the others having been lost, but you can download instructions free of charge from my website for another N&Z instrument that cover this pocket forecaster - CLICK HERE
THIS ITEM IS NOT A BAROMETER