He denied the diurnal rotation of the earth, and was attacked by Kepler and Mersenne, and accused of magic by Gassendi.
Kircher's work is less scarce than that of Mersenne, but also less important.
Mersenne ('Harmonie universelle,' Paris, 1636) mentions him as a brilliant player.
He might have tried it, says Mersenne, with a166 common balance.
Why should Synesius, asks Mersenne, consider himself unfortunate, because he had not a hydrometer?
His own observation, and the reports of Mersenne, furnished his data.
Mersenne communicated this discovery to Descartes, who, treating the matter as easy, sent a short demonstration of his own.
In 1642 he was engaged by Mersenne in controversy with Descartes.
It is unlikely that Descartes should have been ignorant of a writer well known to Mersenne and Huet.
Mersenne mentions that they existed in two sizes, one a fifth above the usual pitch and the other an octave above.