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wood to store and display its poems and drawings. Its memory, analo- gous to a modern read-only computer memory, is a set of 96 brass cam mechanisms.

A cam is a disk mounted on a rotating shaft. Resting on the rim of the disk is the cam follower, a finger free to move up and down as the disk rotates. If the cam is perfectly round, the finger does not move. But if the cam is an oval, a heart, or some other shape, the follower moves up and down as the cam spins. This old idea is still used in automobile engines where cams on the camshaft open and close valves to control the flow of air and fuel into the cylinders. In Maillardets figure, cam followers attached to the writing arm deter- mine its motion in three dimensions. The corresponding cams are intricately shaped so that the motions trace out the letters and lines of the poems and figures, while other cams move the left hand, head, and eyes.

It is fascinating to watch the delicate movements that this ar- rangement imparts, as I found when I was permitted to see the Draughtsman-Writer in action at the Franklin Institutea far more elegant, if slower, method of printing than a computers laser printer. Winding up the springs was no easy matter, because it takes massive coils to turn the heavy cams. When a sheet of blank paper was in- serted under the hand, and it began to write with its pen, I felt a sense of anticipation as the image or lines of poetry began slowly to take shape, stroke by stroke.The results were worth waiting for: delicately drawn images with a good deal of detail and finesse, and for the words, the finest eighteenth-century copperplate script. Best of all was when the hand wrote Ecrit par LAutomate de Maillardet,a message sent directly from the figures maker two centuries ago.

We can only admire the effort and dedication it must have taken to cut brass into precisely the right shapes to form intricate lines on paper, but it is exactly the difficulty of carrying out, and later chang- ing,mechanical programming that prevents cams and clockwork from giving truly lifelike responses.There can be no surprises as automata like the Draughtsman-Writergo through their paces, because a given set of cams always runs through the identical program and pro- duces the identical motions and marks on paper. Short of bringing in

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