One Good Turn: A Natural History of the Screwdriver and the Screw (4 page)

It is December and I am the only visitor in the cavernous, cold building. Before leaving I drop into the museum library, run by the Bucks County Historical Society, to which Mercer presented the museum after its completion. Several people are working at long tables. It is the only part of the building that is heated; I will at least get warm and perhaps come across something useful. The card index has only two entries for screwdrivers, both books that I have read. There are several copies of Mercer’s own book, as well as reprints of Moxon and other standard texts familiar to me.

Browsing through the stacks, I come across a book on nineteenth-century English tool manufacturers in Sheffield. This privately published book—its typed pages bound in a heavy leather cover—is relatively recent, but it is unlikely I would have found it elsewhere; it is one of only
750
copies printed.
¹³
Inside are reproductions of pages from English tool manufacturers’ catalogs.
Sheffield, then the center of the British steel industry, produced probably the finest tools in the world. According to the author, Kenneth Roberts, the oldest surviving example of a Sheffield price list is dated
1828
. There, among spokeshaves and squares, I find not one but a whole family of screwdrivers: three inches to fourteen inches long, in black or bright finishes, and in two patterns, Scotch (flat, tapered blades) and London (more elaborate, waisted blades). The prices vary from four shillings and sixpence to twenty-two shillings a dozen; evidently the list was for job-lot buyers. Later catalogs include illustrations of screwdrivers with flat, oval handles, just like the engraving in the
Encyclopédie.
What surprises me, however, is the terminology: sewing machine
turnscrew,
cabinet
turnscrew,
and a small pocket model, the Gent’s Fancy
Turnscrew.
There is even a
turnscrew
bit, for driving screws with a carpenter’s brace. There is no doubt about it. Salaman was right. Despite its absence from my dictionaries,
turnscrew
is a real word, perhaps an older word than
screwdriver.

The Sheffield catalogs in Roberts’s book demonstrate that by the early
1800
s, the demand for screwdrivers was large enough to warrant factory production. The other evidence I had found suggests that the screwdriver appeared sometime in the previous century, perhaps in France.
Turnscrew
is a literal translation of the French word, and the paper trail runs out in
1723
with the
tournevis
entry in my
Dictionnaire Général.
I now have enough material to write a short essay for the
New York Times,
but I have scarcely solved the puzzle of the screwdriver.
¹⁴

T
HERE ARE TOOLS
, such as the handsaw, that develop slowly and are refined over centuries. Others, such as the carpenter’s brace, are adaptations of a new scientific principle. Then there are those inventions that appear seemingly out of the blue. The button, for example, a useful device that secures clothing against cold drafts, was unknown for most of mankind’s history. The ancient Egyptians, Greeks, and Romans wore loose tunics, cloaks, and togas. Buttons were likewise absent in traditional dress throughout the Middle East, Africa, and South Asia. True, the climate in these places is mild, but northern dress was likewise buttonless. Eskimos and Vikings slipped their clothes over their heads and cinched them with belts and straps; Celts wrapped themselves in kilts; the Japanese used sashes to fasten their robes. The Romans did use buttons to ornament clothing, but the buttonhole eluded them. The ancient Chinese invented the toggle and loop, but never went on to the button and buttonhole, which are both simpler to
make and more convenient to use. Then, suddenly, in the thirteenth century in northern Europe, the button appeared.
¹
Or, more precisely, the button and the buttonhole. The invention of this combination—so simple, yet so cunning—is a mystery. There was no scientific or technical breakthrough—buttons can easily be made from wood, horn, or bone; the buttonhole is merely a slit in the fabric. Yet the leap of imagination that this deceptively simple device required is impressive. Try to describe in words the odd flick-and-twist motion as you button and unbutton and you realize just how complicated it is. The other mystery of the button is the manner of its discovery. It is difficult to imagine the button evolving—it either exists or it doesn’t. We don’t know who invented the button and the buttonhole, but he—more likely she—was a genius.

Maybe the screwdriver, like the button, is a medieval invention. I examine a book of engravings and woodcuts by the sixteenth-century artist Albrecht Dürer. Dürer occasionally portrays tools. A woodcut of the Holy Family in Egypt has Joseph using an adze to hollow out a heavy plank. In a Crucifixion scene, a man turns a large auger to drill preparatory holes for the spikes while his mate wields a heavy hammer. The fullest depiction of tools is in the famous engraving
Melancolia I.
A winged female figure is surrounded by an assortment of woodworking tools: a pair of metal dividers, an open handsaw,
iron pincers, a rule, a template, a claw hammer, and four wrought-iron nails. But no screwdriver.
Melancolia I
includes several magical and allegorical objects such as an alchemist’s crucible, a millstone, and an hourglass, and art historians assume that the tools in
Melancolia I
were likewise chosen for their symbolic meanings. The hammer and four nails, for example, probably refer to the Crucifixion. Maybe the screwdriver simply lacked metaphorical weight.

The most famous technological treatise of the sixteenth century was Agostino Ramelli’s
Le diverse et artificiose machine
(Various and ingenious machines), published in Paris in
1588
. Ramelli was an Italian military engineer who had apprenticed with the Marquis of Marigano and moved to France to serve with the Catholic League in their war against the Huguenots. He had a colorful career. During the siege of La Rochelle he was wounded and captured, but escaped—or was exchanged—and a few months later successfully mined under a bastion and breached the fortification. His commander at La Rochelle was Henri d’Anjou, who became Henri III of France, and it was to the king that Ramelli dedicated his book. Capitano Ramelli, as he styled himself, was following in the footsteps of his celebrated countryman Leonardo da Vinci, and he was no less renowned; he is described by a French contemporary as “a true Daedalus as architect and the Archimedes of our
age.”
²
The frontispiece of Ramelli’s book shows a vigorous, bearded man holding a pair of dividers over a model of a fortification, his other, well-manicured hand resting on a steel cuirassier helmet. The author’s portrait is flanked by allegorical figures symbolizing his two vocations: war and mathematics.

Ramelli’s beautifully illustrated compilation of machines and technological devices was the most influential book of its kind. (Leonardo’s notebooks, while celebrated today, were not published until several centuries after the author’s death.) As is to be expected, the Capitano includes a number of siege engines, cunning pontoon bridges that unfold like accordions, scaling machines, and monstrous catapults. He also presents devices for clandestine break-ins: wrenches for tearing loose door bolts, giant clamps for forcing apart iron gratings and portcullises, and jacks for lifting doors off their hinges, “with great ease and little noise.” The latter claim, at least, is doubtful, since there is no provision for keeping the massive door, once free of the hinge, from crashing to the ground.

The majority of the two hundred machines in his book are peaceful devices. Ramelli was fascinated by the problem of raising water and included a variety of waterwheels, pumps, and bucket conveyor belts. There are also domestic gadgets such as automatic fountains and hand-cranked machines for milling flour. The latter
is important since it is the first known example of the use of rollers, rather than millstones. Ramelli’s version of a revolving bookstand is particularly fascinating. Revolving bookstands were not unknown in Ramelli’s day and were used by scholars consulting several heavy tomes in turn. While a conventional bookstand turned horizontally and held four books, Ramelli’s six-foot-diameter bookwheel turned vertically, like a modern Ferris wheel, and could support no fewer than eight books. “This is a beautiful and ingenious machine, very useful and convenient for anyone who takes pleasure in study, especially those who are indisposed and tormented by gout,” he points out with no false modesty.
³
The bookwheel was a mechanical tour de force. To ensure that the open books remained at a constant angle while the wheel turned, he incorporated a complicated epicyclic gearing arrangement, a device that had previously been used only in astronomical clocks. Of course, gravity would have done the job equally well (as it does in a Ferris wheel), but the gearing system allowed Ramelli to demonstrate his considerable skill as a mathematician.
⁴

This splendid folly distracts me—I’m supposed to be looking for screwdrivers. As far as I can see, the heavy wooden bookwheel is held together with pegs. However, elsewhere in Ramelli’s book, I do find screws. The iron legs of the hand-cranked flour mill are attached to a wooden base with slotted screws, one of which is shown partially unscrewed to reveal the threads. This is proof that screws—and presumably screwdrivers—were used more than a hundred years earlier than any of my previous sources had suggested.

Another celebrated medieval technical book is
De Re Metallica.
This treatise on mining and metallurgy was written by Georg Bauer, a Saxon scholar whose Latinized pen name was Georgius Agricola. Agricola, Germany’s first mineralogist, laid the foundation for the systematic and scientific study of geology and mining.
De Re Metallica,
which appeared in
1556
, shortly after his death, is heavily illustrated with woodcuts of mining and smelting machinery: pumps, mining hoists, and furnaces. Since many of the machines are made of wood, Agricola portrays a number of woodworking tools: axes and adzes for preparing heavy timber shoring; hammers and nails; mallets and chisels; and a long-handled auger for hollowing wooden logs into pipes.

He describes how to make the large bellows to be used for smelting iron. The woodcut illustrates the various components: the iron nozzle, the wooden boards, and the leather bellows. Ox hide is superior to horsehide, according to the author, who goes on to advise that “some people do not fix the hide to the bellows-boards and bows by iron nails, but by iron screws, screwed at the same time through strips laid over the hide.”
⁵
I read the passage twice. Yes, he definitely says iron screws, and there, nestled in the bottom left-hand corner of the engraving, is a neat drawing of a screw. The tapered, threaded body is topped by a flat, slotted head. Although the means of driving the screw are not shown, Agricola provides clear evidence of the use of screws as early as the middle of the sixteenth century.