That St Catherine actually existed there is, indeed, no evidence to disprove; and it is possible that some of the elements in her legend are due to confusion with the story of Hypatia, the neo-platonic philosopher of Alexandria, who was done to death by a Christian mob.
His scientific interests are attested by his letter to Hypatia in which occurs the earliest known reference to areometry, and by a work on alchemy in the form of a commentary on pseudo-Democritus.
At Alexandria the noble Hypatia taught, to whose memory her impassioned disciple Synesius, afterwards a bishop, reared a splendid monument.
The murder of Hypatia was the death of philosophy in Alexandria, although the school there maintained a lingering existence till the middle of the 6th century.
The hydrometer is said by Synesius Cyreneus in his fifth letter to have been invented by Hypatia at Alexandria,' but appears to have been neglected until it was reinvented by Robert Boyle, whose "New Essay Instrument," as described in the Phil.