The Evolution of Useful Things: How Everyday Artifacts-From Forks and Pins to Paper Clips and Zippers-Came to Be as They Are.

by Henry Petroski

  There are a lot of difficult problems in design, and their solution necessarily depends not only upon where designers understand the problems with the past to be but also upon how clearly designers see the road to the future. The operators of wheeled vehicles, by their very nature, are forward-looking; the earliest carts were pulled rather than pushed by people who could see the path unobstructed before them, perhaps in imitation of the way they pulled plows, and the advantage of this arrangement is clear to anyone who has tried to put a cart before a horse or backed up a car with a trailer attached. In time, people were replaced by draft animals, of course, and the only kind of wagonlike vehicles that seem to have evolved with their prime mover following rather than leading has been human-powered.

  For a long time in China, where there was such an effective network of waterways, roads and wheeled vehicles did not evolve into so sophisticated a technology as they did in the West. However, one means of land transportation, the Chinese wheelbarrow, which is believed to have appeared about eighteen hundred years ago, did develop into a rather ingenious configuration. The Chinese wheelbarrow has a very large wheel, of three-to-four-foot diameter, which is set close to the center of the vehicle. The wheel’s upper part is enclosed in a wooden framework onto which an enormous burden can be piled and lashed in a careful arrangement that balances itself both side to side and front to back, so that the pusher is little borne upon by the burden and can concentrate on guiding the barrow.

  The Chinese wheelbarrow is so constructed that a massive and bulky load may be lashed to the frame in such a way as to achieve almost perfect balance about the large enclosed wheel. Thus loaded and balanced, the wheelbarrow presents little burden to the handles, and the person pushing it can concentrate on maneuvering the vehicle. (photo credit 13.2)

  This vehicle is said to have evolved from two-wheeled carts that were ineffective in rice paddies, whose dry boundaries, on which the wheels worked best, were often little more than narrow-topped embankments. A single-wheeled vehicle could be negotiated along the flattened tops of embankments on which a double-wheeled one could not, but even the single wheel of a pulled wagon could easily slip off the narrow divide unless the puller was exceedingly careful and constantly looked back over his shoulder. Keeping the path in view before the wheel was thus the way to proceed.

  Beyond also having a single wheel, the Western wheelbarrow bears little resemblance to its Chinese counterpart, and appears to have developed entirely independently, from a wheelless hod carried stretcherlike by two men. Used in mining and construction work, where narrow passageways and temporary bridges were the rule, the two-man hod was essentially a box with handles extending front and rear. Though this hod was perfectly effective for moving its burden relatively short distances, its great disadvantage was that it could not be operated by a single man. But adding a wheel between one set of handles removed this fault, for now a single man could move the load, bearing no more of the burden than before. The two-man hod was no doubt guided by the leading man, and so the earliest Western wheelbarrows might have been pulled rather than pushed. But the disadvantages of doing this along a narrow plank would have been as evident as those of doing it on the ridge between rice paddies, and so the manner of pushing the wheelbarrow, albeit in an awkwardly stooping fashion, to give the pilot-navigator maximum visibility of the path his wheel was taking, would naturally have evolved.

  Looking forward is indeed the essence of design, but artifacts take on their form over the course of long, rough, and frequently precarious roads. When the first horseless carriages were developed, the choices were at least as numerous as those associated with laying out the parts of a motorcycle on a bicycle frame. The designers of the first autos naturally focused on the most innovative aspect of motive power, and did not overwhelm themselves with choices of how to steer the vehicle, whose chassis was still basically a wagon. The role of reins, for example, was played by a lever that extended into the driver’s hand.

  The Western wheelbarrow appears to have developed from a wheelless hodlike device that was carried by two workers. This illustration from Diderot’s L’Encyclopédie shows such a hod in use. The singular disadvantage of this kind of hod, that it required two workers simultaneously, was clearly overcome by adding a single wheel between one pair of handles. (photo credit 13.3)

  With a successor to the horseless carriage firmly established in the automobile—and when roads had been adapted to it rather than it to they—the attention of designers could focus on the details of how it was made and functioned. The American system of manufacture, whereby everything from pins to pistols was either mass-produced by machine or assembled in machinelike fashion, naturally led a Henry Ford to see automobiles manufactured that way. The design of cars was a question of seeing clearly ahead on the road along which cars and the country were heading. All innovators believe they see the road ahead clearly, of course, but on the journey of design all roads fork and fork again into the undergrowth. Which will become the roads more traveled by will depend on style and conformity that designers, no less than poets—if only in retrospect—may lament. And if the choice of which road to take is not obvious, then the shape of the vehicle to travel upon it may be even less so.

  The streamlining of airplanes followed naturally from their failure to move efficiently through the air, but the design of the first Wright aeroplanes concentrated rightly not on style but on the principal design problem of the day—that of controlling the craft. With increasing mastery of that came increasing speed, which in turn raised the drag on the boxy shapes whose aesthetics were of little concern in the rush to human flight (a phenomenon to be repeated seventy years hence in the Gossamer Condor). By the 1930s, the teardrop shape, known since the turn of the century to be the form of least resistance, was incorporated into Boeing and Douglas aircraft, and, being the contemporary artifact that best symbolized the future, the airplane set the style for things generally. The most static of mundane objects were streamlined for no functional purpose, and chromed and rounded staplers, pencil sharpeners, and toasters were hailed as the epitome of design.

  These two wheelbarrows, illustrated in Agricola’s sixteenth-century treatise on mining, clearly have a strong resemblance to the two-man hod depicted two centuries later in L’Encyclopédie. While the wheelbarrow clearly had an advantage over the hod in requiring only one person to transport it, the hod retained an advantage over the wheelbarrow when it came to being emptied onto an elevated work space. Such relative advantages and disadvantages among artifacts lead to diversity rather than extinction. (photo credit 13.4)

  Streamlining American automobiles began with some subtle changes introduced in the 1920s, but the solidly established squarish Fords set the aesthetic standard. Radical streamlining, such as introduced by Buckminster Fuller in his Dymaxion car exhibited in 1935 at the Chicago World’s Fair, was clearly “futuristic,” and hence not taken as seriously as cars of the present. The sensibly streamlined 1934 Chrysler Airflow rounded and tapered the boxy profile, fenders, and windows of contemporary designs, but it was not a commercial success. The immediate postwar period, which the atomic bomb, if nothing else, defined as the future realized, saw the arrival of truly streamlined cars in the 1947 Studebaker. Though the design owed its aesthetic appearance to Raymond Loewy, he clearly acknowledged the indispensable entrepreneurial role of Studebaker’s president in turning sketches to reality. With the arrival of the future, as embodied in the jet-and-atomic age, automobile styling no longer had to hark back to its roots, and the fins of rockets began to ornament the tails of Cadillacs in 1948. Throughout the 1950s, fins grew to amazing proportions, each year’s models outdoing the last for no functional purpose other than that the new style sold cars.

  With the orbiting of the artificial satellite Sputnik in 1957, the space race had begun, and a new design aesthetic was in place. Fins were necessary on the rockets that launched satellites, but the artificial moons themselves needed no streamlining or stabilizers to
orbit in the virtually frictionless void above the earth’s atmosphere. Sputnik was a surprise, of course, and so automobile designers could not use it to define their immediately upcoming models; with time, however, the look of the future was toward the moon and outer space. The lunar excursion module was a contraption worthy of the Wright Brothers, and streamlining was a distinct disadvantage to a space capsule returning through earth’s atmosphere. Designs for interplanetary probes re-emphasized the curiously boxy beauty of the future, and the space shuttle became the vehicle of design as well as of transportation choice. The silhouette of terrestrial vans introduced in the 1980s bears a distinct resemblance to the nose of the shuttle, and names like Ford’s Aerostar leave little to the imagination as to what images they wish to evoke. Automobiles are marketed like hamburgers, and how well the future dreams and detestations of the customer are read, whether in the product per se or in its packaging, can make the difference between commercial success and failure when design must satisfy so many functions that a single form could hardly be expected to follow from them.

  Though all design is necessarily forward-looking, all design or design changes are not necessarily motivated by fickle style trends, whether they be in the environmental politics of plastic packaging or in the patriotic images of advanced technology. The best in design always prefers substance over style, and the lasting concept over the ephemeral gimmick. Design problems arise out of the failure of some existing thing, system, or process to function as well as might be hoped, and they arise also out of anticipated situations wherein failure is envisioned.

  Ralph Caplan’s book By Design is distinguished by the intriguing situation described in its subtitle: Why There Are No Locks on the Bathroom Doors in the Hotel Louis XIV. Caplan writes of the bathroom-door object lesson as “an ingenious example of the product-situation cycle” and as “the perfect fusion of product and circumstance, and a demonstration of the design process at its best.” His language is more that of the industrial designer than of the engineer, but the hotel problem that Caplan highlights is indeed a wonderful model for how designers must always look ahead, to the future situations and circumstances in which their product will be employed—and to how it might fail.

  Before it was destroyed by fire, L’Hôtel Louis XIV, which was located on the waterfront in Quebec, advertised private baths. However, their privacy was of a limited and precarious kind, for each bath was located between a pair of guest rooms, both of which opened into it. This arrangement is not uncommon in private homes, where bedrooms share a bathroom or where a bathroom opening into a bedroom also opens into a hallway. In all such situations, the basic design objective is to provide privacy for whoever might be using the bathroom. This can be achieved in many ways, of course, and the most obvious and common way is to have locks on each of the doors, so that the bathroom user may bar others from entering. The failure of this solution is frequent and frustrating: the person who has finished with the bathroom forgets to unlock the second door, causing at least a little inconvenience for the next user who tries to enter it. In bathrooms shared by siblings, screaming through the locked door may or may not get results, but generally there is little more than the temporary inconvenience of having to go around to the other door or to another bathroom in the house. Families that find bathroom doors too frequently locked can remove all locks from the doors and trust everyone to knock before entering.

  In the case of bathrooms shared by unrelated guests, the problem is less easily solved. I once stayed in a wonderful old home across the street from Washington University in St. Louis in which two guest rooms shared the same bathroom. Individual guests were expected to come and go at odd hours, and they often wished to leave irreplaceable things like slides and manuscripts in their rooms. Hence, it was desirable that the rooms could be locked against entry from both the hall and the bathroom and, at the same time, that both bathroom doors could be locked from the inside so that privacy could be assured. The arrangement no doubt resulted in many frustrated guests finding themselves locked out of the bathroom, the other guest not in, and the housekeeper nowhere to be found. The measures taken to avoid this situation consisted of a nicely printed sign placed prominently on the dresser beside the bathroom door, reminding each guest to unlock the other guest’s door before leaving the bathroom. I am sure I was not the only guest who suffered from the inadequacy of that solution.

  Whether it was the repeated failure of guests to remember to unlock their neighbors’ doors or some uncommon foresight on the part of the Louis XIV to anticipate the failure of locks to provide fail-safe access to an empty private bathroom, the hotel solved the problem in an ingenious way. Each bathroom door did have a lock on the guest-room side, of course, for otherwise a stranger could come in through the common bathroom, but there were no locks at all on the insides of the bathroom doors. To gain privacy, a guest hooked together in the middle of the room the ends of the three-and-a-half-foot lengths of leather thong attached to each doorknob. Even if the leathers stretched tautly across the bathroom interfered a bit with movement inside, they effectively prevented either door from being pulled open while the bathroom was occupied. However, to open either one of the doors to leave the bathroom, the thongs had to be unhooked, thus unlocking both doors simultaneously.

  Focusing too closely on the immediate design problem, whether it be locking bathroom doors for privacy or canning food for preservation, frequently results in solutions that themselves give rise to more difficult design problems in the future. In the days before plastic was ubiquitous, waste baskets and trash cans were commonly made of metal, and they were emptied by being turned upside down into large collection barrels or bins. Throwing an apple core or a banana peel into a waste basket could leave on its bottom a reminder of lunch that lingered in the office air for days. Disposing of an “empty” can of soda in the waste basket often dripped a sticky mess onto the bottom. In time, a waste basket could become rather crusty and sticky, and washing the metal container, whose finish had become scratched, dented, and worn off during years of being banged about in the emptying process, only caused it to rust and become unsightly. When plastic bags became almost universally used as waste-basket and trash-can liners, they seemed to promise not only a relief from unsightly and unsanitary conditions but also a more efficient and pleasant means for janitors and cleaning crews to empty out the trash. Full bags could just be lifted out of the waste baskets and replaced with clean bags. Larger trash containers in public places were to work in a similar fashion, and there was to be a gain in convenience on the part of both trash disposers and trash collectors. The former would be surrounded by cleaner waste baskets and cans, and the jobs of the latter could be done more easily and conveniently.

  This sketch of one of the bathrooms in L’Hôtel Louis XIV shows leather thongs attached to the doorknobs and fastened together by the occupant (not shown) to ensure privacy. The occupant cannot leave without uncoupling the thongs, and so cannot forget to unlock the door to the room of the person sharing the bathroom. (photo credit 13.5)

  In practice, what seems largely to have happened is that the bags have altered the behavior of everyone concerned with their use and disposal, resulting, in some cases, in what is arguably an unforeseen decrease in the level of sanitation and appearance. Because the plastic bags, at least when free of rips and tears, do not leak, many people seem to have become much less thoughtful about what they throw into the trash. Half-empty yogurt containers, half-full cans of soda, and other lunchtime leftovers that might once have been taken to the restroom to be washed down the drain, seem more and more to be tossed away without a second thought. After all, the plastic bag will contain them and be removed before the mold or flies arrive. Many of those who empty waste baskets seem to have developed a different kind of expediency, emptying the waste basket of its contents the old way, by turning it upside down. The plastic bag is not always replaced, perhaps to save on supplies, or to save the time of having to fit another, often ill-fitt
ing, bag over the waste basket, and thus to have more time to spend on other chores or pleasures. As a result, residue can now collect in the bottom of plastic liners, at least those that have not become punctured, and offices may be no more sanitary or fragrant than before.

  The situation with public trash cans seems no better. The proliferation of fast and prepackaged food has increased the amount of food-contaminated waste. Since so much of this food and drink is not all that palatable to begin with, plastic-lined trash cans are frequently full of rather ripe and wet garbage. Where squirrels are legion, they often forage about in the trash cans, surprising quite a few passersby with the noises they create inside the dark receptacles and startling more by clambering out as footsteps approach. The squirrels, if not the sharp edges of waste, frequently puncture the plastic bags, which are usually full to overflowing, especially after long weekends. Being so full and foul, the bags are replaced with clean ones, but an early-morning walk in the wake of the garbage pickup reveals a host of sticky trails converging from trash containers to wherever the truck was parked. Because so much of the trash is light and bulky, the garbage truck is equipped with a compactor that allows a good number of bags to be fitted into each truckload, but compacting a plastic bag is like squeezing a grapefruit half, and the liquid naturally squirts about and follows the law of gravity. The truck seems incapable of containing all the liquid, and so it leaks out the bottom and onto the pavement. This having been noticed by the trash collectors, they have come to park their truck over storm drains, so that the bulk of the liquid drops into the sewer. But in dry weather, the slop just sits there and cooks into a foul soup. By afternoon on some days, the stench can be unbearable.