*
vii
PREFACE
It is now a third of a century since the Rar a Arithmetic a was
published, and in that space of time there have been many
discoveries in the held of bibliography with which it was con
cerned. Mr. Plimpton passed away in 1936, and to the last he
continued to add to the several branches of his large library —
arithmetics printed before 1601, medieval manuscripts relating
chiefly to mathematics, books and manuscripts concerned with
history, religion, geography, calligraphy, and belles lettres in
various languages. Some years before his death he had in mind
a list of addenda to the Rar a Arithmetica which should include
the acquisitions made by the library during the preceding period
of thirty years. In this he also proposed to add such information
relating to other works and editions as had come to his attention
through recent catalogues of important public or private libraries
or those of prominent and reliable dealers.
Mr. Plimpton was well aware of the value of adding the names
of publishers and the value of brief descriptions of such editions
as were not in his own library, including complete collations, the
names of the libraries consulted, and the present owners in case
of permanent collections, but this would require an amount of
space that would prohibit wide circulation. As the Rara Arith
metica stood it had served and still serves the original purpose
of its publication. Today there are few prominent dealers' lists
of earlv literature that fail to refer to the Rara Arithmetica as
an aid to scholars in the history of this branch of elementary
mathematics.