The want of correct means of measuring time and temperature was severely felt; the clepsydra of Ctesibius answered very imperfectly for the former, the hydrometer floating in a cup of water for the latter; it measured variations of temperature by variations of density.

Philadelphus, who toward the close of his life was haunted with an intolerable dread of death, devoted much of his time to the discovery of an elixir.

For such pursuits the Museum was provided with a chemical laboratory.

In spite of the prejudices of the age, and especially in spite of Egyptian prejudices, there was in connection with the medical department an anatomical room for the dissection, not only of the dead, but actually of the living, who for crimes had been condemned.
3.

For the diffusion of knowledge.