section. The necessary degree of specialization in exact
knowledge is so great that it is only by following one or at
most very few furrows that the delving of research can meet
with any reward of treasure. How then should it be possible
to estimate the value of the work of one of whom it may be
claimed that he took all knowledge as his province? Of
whom the king at whose court and in whose service he
passed the last three years of his life has left it on record
that he did not believe that there had ever come into the
world a man who had known so much! All that may be
attempted is to examine as it were a few facets of the beryl.
In the thousands of pages of his manuscript he has left the
mirror of his thoughts, and there his mind may be seen at
work, moving among the phenomena of nature and the in-
herited knowledge of antiquity, trying all things, expound-
ing all things, proving all things.

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