e problems of kinematic synthesis are considered, however, it
is difficult to see how important new ideas can fail to be produced.

[Footnote 126: R. S. Hartenberg and J. Denavit, "Kinematic Synthesis,"
_Machine Design_, September 6, 1956, vol. 28, pp. 101-105.]

An annual Conference on Mechanisms, sponsored by Purdue University and
_Machine Design_, was inaugurated in 1953 and has met with a lively
response. Among other manifestations of current interest in mechanisms,
the contributions of Americans to international conferences on
mechanisms reflects the growing recognition of the value of scholarly
investigation of the kind that can scarcely hope to yield immediately
tangible results.

While we look to the future, one may ask how a lengthy view of the past
can be justified. It seems to me that there is inherent in the almost
feverish activity of the present the danger of becoming so preoccupied
with operational theory that the goals may become clouded and the
synthesis (let us put it less elegantly: the design) of mechanisms may
never quite come into focus. If one knows nothing of the past, I wonder
how he can with any confidence decide in what direction he must turn in
order to face the future.

Acknowledgment

I am grateful to Professors Richard S. Hartenberg and Allen S. Hall,
Jr., for reading the manuscript, making helpful comments, and suggesting
material that I had not found. The errors, however, are mine.

Additional References

The following list of additional reference material on kinematics may be
of help to readers who desire to do independent research. The material
is listed according to the section headings in the text of the present
article.

TO DRAW A STRAIGHT LINE

KEMPE, A. B. _How to Draw a Straight Line._ London, 1877.

Contains a useful bibliography. Reprinted in _Squaring the Circle and
Other Monographs_, New York, Chelsea Publishing Company, 1953.

Much attention has been given to straight-line mechanisms since the time
of Kempe; at least a half dozen articles have appeared in the United
States since 1950, but I did not investigate the literature published
after 1877.

SCHOLARS AND MACHINES

BECK, THEODOR. _Beitraege zur Geschichte des Maschinenbaues._ Berlin,
1899.

Reviews of early works, such as those by Leonardo da Vinci, Biringuccio,
Besson, Zonca, etc.

BORGNIS, GIUSEPPE ANTONIO. _Traite complet de mecanique appliquee aux
arts._ Paris, 1818-1821, 9 vols.

Conta