Photograph, engraving of a table teaching making and use of a weatherglass, 1631 Photograph, engraving of a table teaching making and use of a weatherglass
Standard humidity units, 3, used to calibrate and adjust instruments, prepared by Humitec Ltd, West Sussex, 1994 Standard Humidity Units
Reconstruction absorbtion hygrometer based on Leonardo da Vinci drawings Reconstruction absorbtion hygrometer