ly to determine velocities of various points
on the same link. Angular velocity ratios were frequently noted. In the
third edition, published in 1921, linear and angular accelerations were
defined, but no acceleration analyses were made. Velocity analyses were
altered without essential change. The fourth edition (1930) was
essentially unchanged from the previous one. Treatment of velocity
analysis was improved in the fifth edition (1938) and acceleration
analysis was added. A sixth edition, further revised by Prof. V. L.
Doughtie of the University of Texas, appeared in 1947.

[Footnote 112: Peter Schwamb and Allyne L. Merrill, _Elements of
Mechanism_, New York, 1904. In addition to the work of Reuleaux and
Rankine, the authors acknowledged their use of the publications of
Charles MacCord, Stillman W. Robinson, Thomas W. Goodeve, and William C.
Unwin. For complete titles see the list of selected references.]

Before 1900, several other books on mechanisms had been published, and
all followed one or another of the patterns of their predecessors.
Professors Woods and Stahl, at the Universities of Illinois and Purdue,
respectively, who published their _Elementary Mechanism_ in 1885, said
in their preface what has been said by many other American authors and
what should have been said by many more. "We make little claim to
originality of the subject-matter," wrote Woods and Stahl, "free use
having been made of all available matter on the subject.... Our claim to
consideration is based almost entirely on the manner in which the
subject has been presented." Not content with this disclaimer, they
continued: "There is, in fact, very little room for such originality,
the ground having been almost completely covered by previous
writers."[113]

[Footnote 113: Arthur T. Woods and Albert W. Stahl, _Elementary
Mechanism_, New York, 1885.]

The similarity and aridity of kinematics textbooks in this country from
around 1910 are most striking. The generation of textbook writers
following MacCord, Woods and Stahl, Barr of Cornell, Robinson of Ohio
State, and Schwamb and Merrill managed to squeeze out any remaining
juice in the subject, and the dessication and sterilization of textbooks
was nearly complete when my generation used them in the 1930's.
Kinematics was then, in more than one school, very nearly as it was
characterized by an observer in 1942--"on an intellectual par with
mechanical drafting."[114] I can recall my own naive b