influenced by him, praised him highly as a poet, but on this subject opinions were divided. Since
only fragments of his writings have survived, his poetic merit must remain in doubt.
It is necessary to deal separately with his science and his religion, as they are not consistent with
each other. I shall consider first his science, then his philosophy, and finally his religion.
His most important contribution to science was his discovery of air as a separate substance. This
he proved by the observation that when a bucket or any similar vessel is put upside down into
water, the water does not enter into the bucket. He says:
"When a girl, playing with a water-clock of shining brass, puts the orifice of the pipe upon her
comely hand, and dips the waterclock into the yielding mass of silvery water, the stream does not
then flow into the vessel, but the bulk of the air inside, pressing upon the close-packed
perforations, keeps it out till she uncovers the compressed stream; but then air escapes and an
equal volume of water runs in."
This passage occurs in an explanation of respiration.
He also discovered at least one example of centrifugal force: that if a cup of water is whirled
round at the end of a string, the water does not come out.
He knew that there is sex in plants, and he had a theory (somewhat fantastic, it must be admitted)
of evolution and the survival of the fittest. Originally, "countless tribes of mortal creatures were
scattered abroad endowed with all manner of forms, a wonder to behold." There were heads
without necks, arms without shoulders, eyes without foreheads, solitary limbs seeking for union.
These things joined together as each might chance; there were shambling creatures with countless
hands, creatures with faces and breasts looking in different directions, creatures with the bodies of
oxen and the faces of men, and others with the faces of oxen and the bodies of men. There were
hermaphrodites combining the natures of men and women, but sterile. In the end, only certain
forms survived.
As regards astronomy: he knew that the moon shines by reflected light, and thought that this is
also true of the sun; he said that light takes time to travel, but so little time that we cannot observe
it; he knew that solar eclipses are caused by the interposition of the moon, a fact which he seems
to have learnt from Anaxagoras.