tracted roots, multiplied, and divided, as well as adding
and subtracting. In 1673, he visited London, where he
met Boyle and Oldenburg, and was made a member of
the Royal Society, largely on account of his calculating-
machine. In this same year, the Elector of Mainz died, and
Leibniz was without an official position. He was offered
the post of Librarian to the Duke of Brunswick at Han-
over. He put off his decision as long as he could, hoping
for something more congenial to his tastes. Finally, in
1676, he accepted the offer and went to Hanover, where
he lived till his death in 1716. On his way to Hanover, he
spent four weeks in Amsterdam. Here he read everything
of Spinoza's which Spinoza could be persuaded to let out
of his hands and finally was allowed to meet Spinoza him-
self. He discussed with him those parts of the Ethics which
he had been permitted to read. From this time forward,
Leibniz had to be contented with letters to keep him in
touch with fellow philosophers and mathematicians. The
only journeys he was able to make were in connexion with
his duties at the Hanoverian court. He embarked upon a
history of the House of Brunswick, and sometimes had to
travel to consult records. One may regret that so much
of his time was taken up with work not calling upon his
special talents, but it would not have been like Leibniz to
do anything half-heartedly which he had undertaken.

Students of philosophy have sometimes blamed Leibniz
for his seeming contentment with a life in which his ener-
gies were largely given to the service of princes. The very
form of his philosophical writings was determined by the
interest which his patrons felt, as amateurs, in his specula-
tions. Bertrand Russell goes so far as to say that Leibniz had
two philosophies, a bad one with which he pleased princes
and, even more, princesses, and a good one which he tried
out on Arnauld by letters. Finding from Arnauld's replies
that it was likely to be considered unorthodox, he kept it

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