His fanciful philosophical suggestions have never been of the slightest practical use.

No one has ever thought of employing them.

Except among English readers, his name is almost unknown.
To Da Vinci I shall have occasion to allude more particularly on a subsequent page.

Of his works still remaining in manuscript, two volumes are at Milan, and one in Paris, carried there by Napoleon.

After an interval of about seventy years, Da Vinci was followed by the Dutch engineer, Stevinus, whose work on the principles of equilibrium was published in 1586.