© Science Museum / Science & Society Picture Library
Engraving by Hausard, taken from 'Memoires sur la Meteorologie' (1788) by le P Cotte. Cotte, Canon of the Cathedral of Laon in France, and a man of scientific letters, was encouraged to write the book after the succes of his earlier treatise on meteorology. He was linked with the Academie des Sciences in Paris and the Meteorological Society of the Palatinate at Mannheim, amongst others. His published work was very well illustrated with the best equipment of his day. A eudiometer is an instrument used to measure and analyse gases and air purity.