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No. 256:
Reuleaux's Machines

Today, we look for the soul of a machine. The University of Houston's College of Engineering presents this series about the machines that make our civilization run, and the people whose ingenuity created them.

Franz Reuleaux was born in Eschweiler, Germany, in 1829, while engineering education was in its infancy. He trained as an engineer in several of the new German schools of engineering. In 1856 he himself became a professor of machine design.

Reuleaux published his first book in 1861 -- a machine-design handbook with the odd title, The Constructor. The book was popular in its time, but a 20th-century expert shrugged it off as "a recipe book"!

Reuleaux's field was kinematics. The nature of the subject displays his genius, but it also shows us why much of the 20th century passed him by. Kinematics is the analysis of machine motions without regard to the forces that drive them. The motions of gears and linkages can be very sophisticated. The mechanism that rotates and extends a robot's arm from one position to another, for example -- it's far from simple. Motion is the first problem a machine designer has to face. Reuleaux eventually went aground on the unhappy fact that it is not the last.

In 1875 Reuleaux published a strong and philosophical book on kinematics, and it was hailed as definitive. In it he wove today's scheme for classifying mechanisms and machine motions. But machines do more than just move. They bear and exert forces. They wear out. They're made of fallible materials.

Engineers soon wanted to see the theory of motions related to these matters. They wanted it brought down to the hard earth. Reuleaux eventually wrote a second book that addressed such issues; but by then he was 71, and he'd lost his audience.

Reuleaux's wide-ranging mind was more concerned with beauty than it was with the needs of the marketplace. He translated Longfellow's Hiawatha into German. He published travel journals. And as German science-based engineering gave way to a view of engineering that began and ended in practice, he was left behind.

Yet he provided the whole theory of machine motions. Today's work on robotics forces us to go back and reread Reuleaux, and when we do, his words have a haunting quality. Here he explains how all machine motions reduce to rolling action:

The machine becomes instinct with a life of its own through the rolling [motion] everywhere connected with it ... In the midst of [their distracting noise, machines] carry on their noisless ... rolling. [These motions are] the soul of the machine.

Machines ultimately exist in hard reality, but Reuleaux reminds us that the soul of the machine reflects the soul of its inventor -- that while we surely want to end in hard reality, it is not the right place to begin.

I'm John Lienhard, at the University of Houston, where we're interested in the way inventive minds work.

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