His own observation, and the reports of Mersenne, furnished his data.
Hartlib, though he scarcely takes rank with Mersenne as a scientist, was no less influential.
Why should Synesius, asks Mersenne, consider himself unfortunate, because he had not a hydrometer?
Mersenne calls this the simplest form of chalumeau or wheat-stalk (tuyau de bl).
In 1642 he was engaged by Mersenne in controversy with Descartes.
