ppear to have been the sparks for the conflagration
that still is increasing in extent and intensity. According to summaries
in _Engineering Index_, R. Kraus, writing on the synthesis of the
double-crank mechanism, drew fire from the Russian Z. S. Bloch, who, in
1940, discussed critically Kraus's articles and proceeded to give the
outline of the "correct analysis of the problem" and a general numerical
solution for the synthesis of "any four-bar linkage."[120] Russian work
in mechanisms, dating back to Chebyshev and following the "Chebyshev
theory of synthesis" in which algebraic methods are used to determine
paths of minimum deviation from a given curve, has also been reviewed
elsewhere,[121] and I can add nothing of value.

[Footnote 119: Grodzinski, Bottema, De Jonge, and Hartenberg and
Denavit. For complete titles see list of selected references.]

[Footnote 120: My source, as noted, is _Engineering Index_. Kraus's
articles are reported in 1939 and Bloch's in 1940, both under the
section heading "Mechanisms."]

[Footnote 121: A. E. Richard de Jonge, "Are the Russians Ahead in
Mechanism Analysis?" _Machine Design_, September 1951, vol. 23, pp. 127,
200-208; O. Bottema, "Recent Work on Kinematics," _Applied Mechanics
Reviews_, April 1953, vol. 6, pp. 169-170.]

When, after World War II, some of the possibilities of kinematic
synthesis were recognized in the United States, a few perceptive
teachers fanned the tinder into an open flame.

The first publication of note in this country on the synthesis of
linkages was a practical one, but in conception and undertaking it was a
bold enterprise. In a book by John A. Hrones and G. L. Nelson,
_Analysis of the Four Bar Linkage_ (1951), the four-bar crank-and-rocker
mechanism was exhaustively analyzed mechanically and the results were
presented graphically. This work was faintly praised by a Dutch scholar,
O. Bottema, who observed that the "complicated analytical theory of the
three-bar [sic] curve has undoubtedly kept the engineer from using it"
and who went on to say that "we fully understand the publication of an
atlas by Hrones and Nelson containing thousands of trajectories which
must be very useful in many design problems."[122] Nevertheless, the
authors furnished designers with a tool that could be readily, almost
instantly, understood (fig. 45), and the atlas has enjoyed wide
circulation.[123] The idea of a geometrical approach to synthesis has
been exploited by oth