appreciated in our own time than they could have been during the
preceding centuries. He has been unjustly accused of having
squandered his powers, by beginning a variety of studies and then,
having hardly begun, throwing them aside. The truth is that the
labours of three centuries have hardly sufficed for the elucidation
of some of the problems which occupied his mighty mind.

Alexander von Humboldt has borne witness that "he was the first to
start on the road towards the point where all the impressions of our
senses converge in the idea of the Unity of Nature" Nay, yet more
may be said. The very words which are inscribed on the monument of
Alexander von Humboldt himself, at Berlin, are perhaps the most
appropriate in which we can sum up our estimate of Leonardo's
genius:

"Majestati naturae par ingenium."

LONDON, April 1883.

F. P. R.







CONTENTS OF VOLUME I.