Engines of Our Ingenuity

No. 966:
CONTINUITY OF FORM

by John H. Lienhard

Click here for audio of Episode 966.

Today, thoughts about the "user interface" and technological change. 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.

Have you ever noticed how form survives technological revolutions? It's astonishing when you think about it. Huge similarities always remain when our best machines undergo radical change.

The circular face of a sundial, with its shadow moving left to right, was copied straight into the faces of water clocks. Water clocks used a float, in a steadily filling or draining tank, to tell time. But that float drove gears, and the gears drove hands around a dial.

Then the tick-tock mechanical escapement radically improved clock accuracy. It also made clocks smaller and cheaper. But, changed as they were, clocks still had dials, bells, and gears. Medieval writers had almost nothing to say about the new mechanism inside, so historians still aren't sure when that change took place. You see, the outward form, the clock face, did not change.

Then, around 1920, another radical change. This time, electrical timing elements used the steady oscillation of alternating current to replace the mechanical escapement. Accuracy took another leap forward. But clocks still looked the same.

Now quartz crystals confuse the issue again. My desk clock not only has the circular face of a sundial or a water clock. It also has a second hand that moves in little jumps -- as though it were controlled by an escapement mechanism. Designers understood on a visceral level that the meeting ground between the user and the machine should never change any more than it has to.

Try another technology: printed books tell the same story. Hand-written manuscript books had the familiar features of books today. Pages were folded into gatherings and gatherings sewn together and laced between hard covers, as they still are today.

When Gutenberg began printing with movable metal type, he did far more than just copy the old structure of books. He also made print look just like the work of scribes. It often takes a trained eye to tell an early printed book from a manuscript book. Movable type made books cheap and abundant. Yet we readers still receive information the same way we did 1000 years ago.

Now I sit before a personal computer, working on what's clearly recognizable as a typewriter keyboard. Once more, the place where I meet the machine, for all its imperfect arrangement, is old and well loved. It simply will not be abandoned.

Friends ask me, over and over, "How much change will we have to undergo?" The answer is a surprise: where the user meets the machine is where we will not tolerate change -- even though the machine itself is mutating into something so different as to redirect human history.

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

(Theme music)


I'm indebted to Pat Bozeman, UH Library, for making a strong point of the way that an essential continuity rides through huge technological changes. I am grateful to Judy Myers and Jeff Fadell, also of the UH Library, for pointing out that continuity is vested in the so-called "user interface" of a machine -- not in its operating principle.



Image Courtesy of Special Collections, UH Library

Top of a French page from the Gospel according St. Mark, dated AD 1230. Note the first three letters of the Evangelist's name, MARCUS, at the top. That means that this is a left-hand page.


Image Courtesy of Special Collections, UH Library

Top of a Gutenberg Bible printed in 1455 or 1456. This page is a nearly perfect imitation of the 225-year-old manuscript page above. It doesn't have blue lines to guide the scribe, and it is printed on paper.




From the 1832 Edinburgh Encyclopaedia

Details of clepsydra (water clock) operation



From the 1832 Edinburgh Encyclopaedia

A very early foliot and verge escapement mechanism




The Engines of Our Ingenuity is Copyright © 1988-1997 by John H. Lienhard.

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