his falling will carry up the wind, which the sail will hold, by
which means he does not fall suddenly but descends little by
little. The size of the sail should be measured to the man.' By
this last, evidently, Veranzio intended to convey that the sheet
must be of such content as would enclose sufficient air to
support the weight of the parachutist.

Veranzio made his experiments about 1617-1618, but, naturally,
they carried him no farther than the mere descent to earth, and
since a descent is merely a descent, it is to be conjectured that
he soon got tired of dropping from high roofs, and took to
designing architecture instead of putting it to such a use. With
the end of his experiments the work of da Vinci in relation to
flying became neglected for nearly four centuries.

Apart from these two experimenters, there is little to record in
the matter either of experiment or study until the seventeenth
century. Francis Bacon, it is true, wrote about flying in his
Sylva Sylvarum, and mentioned the subject in the New Atlantis,
but, except for the insight that he showed even in superficial
mention of any specific subject, he does not appear to have made
attempt at serious investigation. 'Spreading of Feathers, thin
and close and in great breadth will likewise bear up a great
Weight,' says Francis, 'being even laid without Tilting upon the
sides.' But a lesser genius could have told as much, even in
that age, and though the great Sir Francis is sometimes adduced
as one of the early students of the problems of flight, his
writings will not sustain the reputation.

The seventeenth century, however, gives us three names, those of