Cover; August 1996; Scientific American Magazine; by Staff Editor; 1 Page(s)

Table of Contents; August 1996; Scientific American Magazine; by Staff Editor; 2 Page(s)

From the Editors, including Masthead; August 1996; Scientific American Magazine; by Staff Editor; 1 Page(s)

Letters to the Editors; August 1996; Scientific American Magazine; by Staff Editor; 1 Page(s)

50, 100 and 150 Years Ago; August 1996; Scientific American Magazine; by Staff Editor; 1 Page(s)

AUGUST 1946 According to one contention, magnesium will eventually replace iron as the world¿s basic constructional raw material. Hence, it might be feasible to call the next age of man the ¿magnesium age.¿ The element appears to be the only ¿basic¿ material of which the supply is inexhaustible: one cubic mile of sea water contains 9.2 billion pounds of metal in the form of magnesium chloride. It is the lightest of the structural metals, and magnesium¿s so-called ¿fire hazard¿ is only a factor when handling fine powders or the molten metal. However, if magnesium is to become the prime raw material it is not likely to do so for centuries. Its competitors--iron and steel, aluminum and structural plastics--would have to reach a state of depleted supply and high prices.

AUGUST 1896 Interest in the compressed air motor has been shown by the Third Avenue Railroad Company, of New York, which has adopted the system invented by Mr. R. Hardie. In earlier systems, when the air was expanded from the storage flasks, the corresponding reduction of temperature was so great as to cause freezing and choking up of the exhaust passages. In the Hardie system, the cars, one of which is shown in the accompanying illustration, are similar in their general appearance to an ordinary street car. But underneath the seats are sixteen air reservoirs, rolled steel flasks 9 inches in diameter and 20 feet long, and a hot water tank, by means of which the air is heated before it enters the two cylinders of the motor, and the difficulty of freezing exhaust is overcome.

In Focus: Paying Attention; August 1996; Scientific American Magazine; by Leutwyler; 2 Page(s)

When Tom was born, he acted like a "crack baby," his mother, Ann, says. "He responded violently to even the slightest touch, and he never slept." Shortly after Tom turned two, the local day care center asked Ann to withdraw him. They deemed his behavior "just too aberrant," she remembers. Tom¿s doctors ran a battery of tests to screen for brain damage, but they found no physical explanation for his lack of self-control. In fact, his IQ was high--even though he performed poorly in school.

Eventually Tom was diagnosed with attention-deficit/hyperactivity disorder (ADHD)--a condition that typically manifests in young children as inattention or impulsivity and sometimes hyperactivity. These traits make it difficult for ADHD kids to sit still, concentrate and learn. The psychiatrist told Ann that in terms of severity, Tom was 15 on a scale of one to 10. As therapy, this doctor prescribed methylphenidate, a drug better known by its brand name, Ritalin.

Public Eye; August 1996; Scientific American Magazine; by Stix; 2 Page(s)

Last year President Bill Clinton signed an order declassifying hundreds of thousands of photographs taken by the first-generation of military spy satellites in a program that ended in 1972. Within another two years, commercial satellite companies plan to deliver pictures of better quality to anyone with a credit-card number and a Federal Express or an Internet account. They intend to sell snapshots from space that can show details as small as a meter--a close enough view to delineate boats, bridges or houses anywhere on the planet.

The companies have already publicized the imminent arrival of high-resolution satellite images as a boon for business. Real estate agents could furnish prospective buyers with a panoramic look at a neighborhood. Travel agents may provide vacationers with a dramatic overview of a chateau in the Alps.

In Brief; August 1996; Scientific American Magazine; by Leutwyler; 3 Page(s)

The Other White Fish Sea lamprey. These slimy, eellike parasites normally suck the life out of trout and salmon fisheries in the Great Lakes. The Great Lakes Fishery Commission traps 50,000 to 100,000 lamprey every year--sterilizing and releasing the males and sending the females to the landfill. But researchers from the Sea Grant Program at the University of Minnesota at Duluth have a new plan: sell them to the Portuguese! There lampreys are considered a tasty meal. Sea Grant will send a sampler of 80 females overseas this summer.

Making Memories As people age, an enzyme called prolyl endopeptidase (PEP) increasingly degrades the neuropeptides involved in learning and memory. In Alzheimer¿s disease and senile dementia, the process is accelerated, causing memory loss and a shortened attention span. But now researchers in Suresnes, France, have found compounds that prevent PEP from breaking neuropeptides apart. In tests, these chemicals almost completely restored memories in amnesiac rats.

The Wall Falls; August 1996; Scientific American Magazine; by Wallich; 2 Page(s)

Alexandre Chorin and Grigory Barenblatt had been studying turbulence from different perspectives for more than 30 years when they met this past February at the University of California at Berkeley. Chorin works in computational fluid dynamics, calculating the theoretical properties of idealized turbulent flow. Barenblatt is a mathematician who studies the "scaling laws" that engineers employ to extrapolate results from wind-tunnel tests and other small-scale experiments to the real world.

But the two saw ground for collaboration: theoretical studies of turbulence have been limited for some years by the mathematical formulations of fluid flow. Even after extensive refinement of experimental apparatus, discrepancies remained between predicted results and actual measurements. The only way to go forward was to go back and reexamine the foundations of the field, Barenblatt recalls.

Mussel Mayhem,; August 1996; Scientific American Magazine; by Zorpette; 2 Page(s)

When the first zebra mussels were spotted in Lake Erie in 1988, the Cassandras had a field day. Within weeks, there were predictions that the incredibly hardy, prolific creatures would bring on ecological and financial disaster as they wreaked havoc with the lake¿s food chain and clogged the water-intake systems of electric power stations, boat motors and drinking-water facilities.

In fact, in many ways the disaster did not live up to expectations. Chlorine and other chemicals have kept the pesky mollusks away from intakes at far lower costs than were feared. Moreover, there have even been some apparent benefits. The fat little critters are prodigious filterers, absorbing surprising amounts of a variety of pollutants from the water and storing them in their lipids. They have also consumed so much algae, their main food, that large parts of the lake have become visibly clearer.

A New King and His Tiny Minion; August 1996; Scientific American Magazine; by Sinha; 1 Page(s)

Poor Tyrannosaurus rexhas been dwarfed, again. Fossils unearthed in the Kem Kem region of Morocco point to the existence of a dinosaur whose head was five feet, four inches long (1.6 meters), just slightly larger than that of T. rex. The discovery of Carcharodontosaurus, or "shark-toothed reptile," by Paul C. Sereno of the University of Chicago and his colleagues comes right after the finding last year of Giganotosaurusin Argentina. The South American giant and its new African counterpart--along with Sereno¿s other Moroccan find, a smaller species called Deltadromeus, or "delta runner"--are also helping scientists understand exactly when the continents split apart.

Paleogeographers believe that by the end of the Jurassic, some 150 million years ago, the ancient supercontinent Pangaea split into a section called Laurasia, which moved north, and Gondwana, which remained in the south. This idea is supported by fossils showing an evolutionary schism: species unique to each landmass sprung up at about the same time. But until now, this evidence had been restricted to Asia, Europe and South America.

The Blustery Void; August 1996; Scientific American Magazine; by Powell; 2 Page(s)

On March 26 of this year, the Anik E1 telecommunications satellite lost power in one of its solar panel arrays, temporarily interrupting voice, video and data service for its owner, Telesat Canada. In the past, such a mishap might have been vaguely attributed to component failure. But this time, Daniel Baker of the University of Colorado identified a more specific culprit: a bout of inclement space weather.

Outbursts of magnetic flux and charged particles from the sun episodically roil interplanetary space and agitate the earth¿s magnetic field. These disturbances have long been known to induce surges in power grids and to interfere with long-distance navigation and communications signals. Improved understanding of space weather is revealing the true magnitude of the problem, as experienced by Anik E1. Ernest Hildner, director of the Space Environment Center (SEC) in Boulder, Colo., warns that the situation is only going to get worse. With their miniaturized circuits and reduced overall size, modern satellites are increasingly vulnerable, even as their total number continues to grow. Meanwhile the sun is likely to turn ever more restless as it progresses through its current 11-year activity cycle.

Patient, Smell Thyself; August 1996; Scientific American Magazine; by Mirsky; 1 Page(s)

Worried that you have bad breath? Unless vultures are actually circling your mouth, there¿s good news. The problem may not be your breath at all, but your personality.

Researchers at Tel Aviv University decided to study just how bad the breath really was of 38 people whose concerns about their oral malodor drove them to seek medical attention. The researchers published the results in a recent issue of Psychosomatic Medicine. Sixteen patients had themselves come to the conclusion that they had a problem. Another 12 were driven to this conclusion--they claimed that others had complained. The last 10 were getting input from both sides, having decided for themselves that they reeked but having also found the telltale gift-wrapped bottle of mouthwash in their desk drawer.

By the Numbers: Lethal Accidents, 1979-1992; August 1996; Scientific American Magazine; by Doyle; 1 Page(s)

Accidents do not occur at random. People 85 years of age and older are 22 times more likely to die accidentally than are children five to nine years old. The risk for Native Americans is four times that for Asian-Americans and twice that for white Americans or African-Americans. Males suffer accidents at more than twice the rate of females, in part because they are more prone to risky behavior. Alaskans are more than three times as likely as Rhode Islanders to die in an accident. Texans are 21 times more likely than New Jerseyites to die in a natural disaster. Among the 100 most populous counties, Kern County, California (Bakersfield), has an accident fatality rate three times greater than Summit County, Ohio (Akron).

Accidents happen more often to poor people. Those living in pover ty receive inferior medical care, are more apt to reside in houses with faulty heating and electrical systems, drive older cars with fewer safety features, and are less likely to use safety belts. People in rural areas have more accidents than city or suburban dwellers because farming is much riskier than working in a factory or office and because emergency medical services are less readily available. These two factors--low income and rural residence--may explain why the South has a higher accident rate than the North. The high rate in the Mountain States is the result, in part, of the rural nature of the region. Alcohol is an important contributor to many accidents, including not only car crashes but also falls, fires and drowning.

Mouse to Father Rat?; August 1996; Scientific American Magazine; by Beardsley; 2 Page(s)

Mary had a little lamb--and the doctors were surprised," runs a warped version of the nursery rhyme analyzed by the linguist Steven Pinker in his book The Language Instinct. Today the doctors would still be very surprised. But the prospect of a mouse siring a rat, at least, has suddenly become an imminent reality, thanks to a technique developed at the University of Pennsylvania. The process--transplantation of cells that produce sperm--could also allow mammals, including humans, to father multiple offspring years after their death.

The researchers describe in the May 30 issue of Nature how they transplanted sperm-producing cells called spermatogonia from rat testes into mice testes, where the cells made seemingly normal rat sperm that may be capable of fertilizing rat eggs. A companion paper in the June issue of Nature Medicine reports that the spermatogonia can be deep-frozen in liquid nitrogen for long periods--156 days, so far--before they are successfully implanted. The transplanted cells were genetically marked to prove that they were indeed the progenitors of sperm in the recipient testes. The investigators suppressed the immune systems of the mice so they would not reject the foreign rat tissue.

Field Notes: Insects of Generation X; August 1996; Scientific American Magazine; by Schneider; 1 Page(s)

Adozen reporters gather in New Haven, Conn., at Yale University¿s Peabody Museum of Natural History to hear Charles L. Remington speak in animated tones about the momentous event that is under way. In a nearby park, a group of astonishingly long-lived insects is about to make a rare appearance. And Remington, an entomologist of diverse interests, is doing all he can to enlist the help of journalists to ensure that people far and wide take notice.

The insect in the spotlight is the cicada. But the entomological star is not the ordinary, late-summer variety (the so-called dog-day cicada that noisily visits suburban backyards every year). The focus is on Magicicada septendecim, a species that is unique to the eastern U.S. M. septendecim lives most of its 17-year life underground, tapping fluids from tree roots for sustenance. With an uncanny sense of timing, these insects dig their way to the surface in the late spring of their 17th year, shed their final nymphal skin and populate a patch of forest. During their few weeks of adult life, they mate, deposit eggs in twigs and provide a feast for the birds that happen to notice that something special is occurring.

Cyber View; August 1996; Scientific American Magazine; by Browning; 2 Page(s)

The network computer is almost a good idea--but not quite. Now widely touted as the next hot thing from the computer industry, the network computer is in fact shaping up to provide a classic example of how engineers get things wrong. The case for the network computer, or NC, as it is cozily called by big-name boosters such as Oracle, IBM, Apple and Sun Microsystems, is based on perceptive technological analysis, which veers unerringly to the wrong conclusion. Most visions of networked computing currently base their advantages on the convenience of builders and maintainers of computers. Those that actually sell will have to appeal instead to the convenience of users.

The touted advantages of the NC stem from the fact that it is half a computer. The user buys only screen, microprocessor and keyboard, not the disk on which programs and data are stored long-term. So the purchase price is relatively cheap-- about $500. A (preferably high-speed) network link connects the user to the centralized disk storage on which programs and personal data are kept, as well as to the Internet. Because programs are stored centrally, the design minimizes the costs and complexity of managing machines-- upgrading software, backing up data and so on--which can cost up to $3,000 a year at some large companies.

Recently Netted....; August 1996; Scientific American Magazine; by Eisenberg; 1 Page(s)

Debunking Bad Anthropology. Irked by the half-baked anthropology on view at many World Wide Web sites, Candice Bradley, a cultural anthropologist at Lawrence University, started her own page: Classics of Out(land)ish Anthropology (http://www.lawrence.edu/dept/anthropology/classics.html). On it she lampoons the scientific solecisms that catch her eye, from news of Bigfoot to a Web site offering "evidence"--aired on NBC--that humans lived at the time of the dinosaurs ("Human footprints found side-by-side with dinosaur tracks").

One of her favorite targets is the Project Candide Web site; it contains the saga of a trip to Tanzania and Kenya that begins with the voyagers having pizza for the "last time" before departing the U.S. "This is typical of the biased representations of Africa on the Web," Bradley says. "In fact, there are more good restaurants in Nairobi than in most U.S. cities. Pizza is abundant." She also remarks on the safari¿s maps. They "are tinted with a sienna background so that they resemble 17thor 18th-century maps of Africa. They are classic examples of the nostalgia for precolonialism and colonialism so prevalent in depictions of things African."

Magnet on the Brain; August 1996; Scientific American Magazine; by Yam; 1 Page(s)

Children often learn about magnetism by dragging a paper clip through a paper maze with the aid of a magnet held below. Researchers now hope that before long they will accomplish a similar feat in the maze of the human brain with a refined version of a procedure called stereotaxis. The technique, being tested by workers at Stereotaxis, a firm in St. Louis, and at the Washington University School of Medicine, would allow physicians to reach diseased areas of the brain with the least possible damage to healthy tissue.

Stereotaxis is the procedure in which surgeons plunge, say, needles or electrodes straight through the brain to treat a trouble spot deep within. In the process, they tear healthy and perhaps essential neural tissue--a risk complicated if several needles or electrodes need to be inserted, as is sometimes the case. (For instance, to treat Parkinson¿s disease stereotaxically, six drug-delivering needles would be inserted in different spots to saturate fully the deep-seated striatum, which contains the defective tissue.) Physicians try to minimize surgical damage by first reviewing a brainscan image and then avoiding the most crucial areas.

Too Much for too Little; August 1996; Scientific American Magazine; by Aharonian; 1 Page(s)

Every gene sequence that the U.S. Patent and Trademark Office receives must be checked for novelty and obviousness. The PTO uses two massive parallel-processing computers that compare the sequences against five databases; this electronic search is then evaluated by an examiner and, often, a senior examiner. All fairly straightforward.

The problem is that to do this the PTO needs tens of millions of dollars and 100 years--and that¿s just to review the pending patents. According to John Doll, head of the PTO group that handles gene patents, it takes about 65 hours and $5,000 to examine a batch of 100 sequences. But the application fee is only about $800, and some applicants, including Incyte Pharmaceuticals in Palo Alto, Calif., and Human Genome Sciences in Rockville, Md., submit thousands of sequences in an application. As equipment becomes more powerful and automated analysis enables sequences to be tested more quickly for potential pharmaceutical uses, even more applications will be submitted.

The Right Touch; August 1996; Scientific American Magazine; by Sinha; 1 Page(s)

With just a tap of your finger, imagine unlocking your house, withdrawing money from your bank account or even shopping. It may seem like a futurist fantasy, but electronic fingerprint identification can no longer be relegated to the realm of science fiction.

Although the technology has been in the works for a few years--and New York City¿area airports have used it on a limited scale since 1994--it is finally becoming widespread. This past April the New York City police department contracted with two companies specializing in biometric security systems--MORPHO Systems and Identix--to install a fingerprint identification system. Now an officer will be able to scan a suspect¿s fingerprints into a database, take a digitized mug shot, type in other details and then electronically send the entire package to headquarters. The system is expected to be more accurate than current paperwork procedures, sparing police thousands of hours.

One Small Step; August 1996; Scientific American Magazine; by Gibbs; 3 Page(s)

With grand fanfare, the electronics giant Texas Instruments announced in May that it had perfected a process that can produce silicon microchips of far greater detail and complexity than any currently available. Newspapers widely marveled at the innovation; many pointed out that TI is the first to produce chips with features as small as 0.18 micron (millionths of a meter) wide. Some predicted that the microchips would launch a generation of wonderfully smart and compact contraptions.

Such reports were wrong on two counts, but correct on the third. TI was not first. Although that company has prototypes on hand and hopes to have a factory constructed by next year, IBM began shipping small quantities of equally detailed integrated circuits in May. And both TI¿s and IBM¿s processes create tiny transistors that are 0.25, not 0.18, micron in width. (The much misunderstood 0.18-micron measurement refers not to feature size but to the distance current must travel to switch a single transistor.) This long-expected advance is the logical next step beyond the 0.35-micron features that make up the Pentium Pro and PowerPC chips now on the market, but it was not anticipated to occur until 1997.

Coat of Many Colors; August 1996; Scientific American Magazine; by Nemecek; 2 Page(s)

Conventional wisdom has it that red cars attract more speeding tickets. But what about cars that change color? Several new coatings may soon permit drivers to test their legal luck.

Taking cues from nature, chemists have been able to develop paints that derive their colors from interference patterns. The brilliant colors of butterflies, for example, result from multiple layers of extraordinarily thin fibers found in the insects¿ wings. When light falls on the wings, the top layers reflect the rays at a slightly different angle than the bottom layers do. The different reflected wavelengths then interfere with one another, producing new wavelengths that appear as shimmering colors.

Profile: Shelley A. Harrison; August 1996; Scientific American Magazine; by Beardsley; 2 Page(s)

The curving tower of yellow smoke that just lofted Endeavour into the morning sky over Cape Canaveral on Florida¿s east coast is beginning to disperse, and Shelley A. Harrison, whose company has entrusted much of its assets to the space shuttle¿s cargo bay, is beaming. Although he missed a night¿s sleep schmoozing and talking business, Harrison, chairman and CEO of Spacehab, exudes confi- dence. The commercial space business is poised to take off, he believes, and Spacehab has--for now--no competition. "I believe human habitation of space is going to happen, and Spacehab¿s objective is to support it," Harrison declares.

Harrison, possibly the only person at the Kennedy Space Center wearing a suit and tie, is a high-tech venture capitalist with a mission to commercialize the space frontier. His voice is academicprecise, rather than big-business-brash, harking back to his days as a university scientist. But Harrison has the kind of record that commands attention in the world of commerce: one of his early ventures helped to establish the bar codes that now adorn products throughout the developed world. Harrison thinks low earth orbit is a territory as ripe for technological development as the retail stores of the 1970s.

Smart Cards; August 1996; Scientific American Magazine; by Fancher; 6 Page(s)

The semiconductor revolution has advanced to the point where the computing power that once took up an entire room can now be lost among the spare change, house keys or candy wrappers in the average pocket. For more than 10 years, "smart" credit cards incorporating tiny chips have been in use in France and other parts of Europe. A set of standardized contacts on the front of each card supplants or supplements the familiar coded magnetic stripe on the back. Although the U.S. has been lagging in the use of this technology, a series of ongoing pilot programs may soon change that situation. Some pundits have criticized smart cards as a technology endlessly in search of meaningful applications, but the divergent experiences of different countries show that the issues are more complicated.

Curiously, telecommunications policy has been one of the major influences on the deployment of smart cards. In the U.S., where telephone calls are cheap and it is a simple matter to attach a magnetic-stripe reader to a phone line, the fraud-reduction aspects of smart cards are not necessarily worth the extra expense. Instead merchants can dial up a central database to make sure a card is valid before completing a transaction. In Europe, where calls are generally more expensive and connecting modem-equipped devices to phone lines is more difficult, security was a significant driving force behind smart-card introduction.

The Stellar Dynamo; August 1996; Scientific American Magazine; by Nesme-Ribes, Baliunas, Sokoloff; 7 Page(s)

In 1801, musing on the vagaries of English weather, the astronomer William Herschel observed that the price of wheat correlated with the disappearance of sunspots. But the pattern soon vanished, joining what scientists at large took to be the mythology connecting earthly events with solar ones. That the sun¿s brightness might possibly vary, and thereby affect the earth¿s weather, remained speculative.

Thus, in the mid-1980s, when three solar satellites--Solar Maximum Mission, Nimbus 7 and Earth Radiation Budget--reported that the sun¿s radiance was declining, astronomers assumed that all three instruments were failing. But the readings then perked up in unison, an occurrence that could not be attributed to chance. The sun was cooling off and heating up; furthermore, the variation was connected with the number of spots on its face.

Gradients that Organize Embryo Development; August 1996; Scientific American Magazine; by Nüsslein-Volhard; 6 Page(s)

Bears mate in wintertime. The female then retires into a cave to give birth, after several months, to three or four youngsters. At the time of birth, these are shapeless balls of flesh, only the claws are developed. The mother licks them into shape.

This ancient theory, recounted by Pliny the Elder, is one of the many bizarre early attempts to explain one of life¿s greatest mysteries--how a nearly uniform egg cell develops into an animal with dozens of types of cells, each in its proper place. The difficulty is finding an explanation for the striking increase in complexity. A more serious theory, popular in the 18th and 19th centuries, postulated that an egg cell is not structureless, as it appears, but contains an invisible mosaic of "determinants" that has only to unfold to give rise to the mature organism. It is hard for us now to understand how this idea could have been believed for such a long time. To contain the complete structure of the adult animal in invisible form, an egg would also have to contain the structures of all successive generations, because adult females will in time produce their own eggs, and so on, ad infinitum. Even Goethe, the great poet and naturalist, favored this "preformation hypothesis," because he could not think of any other explanation.

Sands of the World; August 1996; Scientific American Magazine; by Mack, Leistikow; 6 Page(s)

When we pick up a handful of sand from the beach and watch it sift through our fingers, we are seeing the product of millions of years of geologic history. Much of this history can be uncovered by examining the particles under magnification, where they give up the secrets of their origin and subsequent travels.

Most sand starts life in mountainous areas as continental rock--primarily as quartz and feldspar. Mechanical breakdown (by the movement of glaciers; by cycles of freezing and thawing) produces boulders and pebbles. Then chemical assault (by vegetation and rain) combines with mechanical disintegration to eat away at these boulders and pebbles, eventually giving birth to individual grains. Geologists define sand as rock fragments having a diameter between 0.05 and two millimeters; larger particles are classified as gravel, smaller as silt.

Probing High-Temperature Superconductivity; August 1996; Scientific American Magazine; by Kirtley, Tsuei; 6 Page(s)

One of the most memorable sessions in physics occurred on March 18, 1987, during a meeting of the American Physical Society. Hastily arranged to accommodate a huge number of postdeadline talks, the gathering in the Hilton Hotel in New York City drew 2,000 physicists. Crammed into a ballroom, with many others spilling into the hallway, they struggled to give and to hear five-minute briefings on the latest ideas and investigations. Dubbed the Woodstock of physics, the session started at 7:30 P.M. and continued until 3 A.M.--even at that hour the excitement was still evident.

The cause of all this academic commotion was the announcement of hightemperature superconductivity. Late in 1986 J. Georg Bednorz and K. Alexander Mfflller of the IBM Research Laboratory in Zurich had reported that a ceramic called lanthanum barium copper oxide lost all electrical resistance when it was cooled to only -238 degrees Celsius, or 35 kelvins (degrees above absolute zero). Although that temperature is still quite frigid, it was nonetheless more than 10 degrees better than the best conventional superconductors, which are made from metals or alloys. Soon thereafter critical temperatures above 90 kelvins were reported and confirmed, and rumors of superconductivity at 130 kelvins and 240 kelvins abounded. If a material could be found that superconducted at room temperature (300 kelvins or so), it would very likely initiate a revolution in modern society.

The Mystery of Lambic Beer; August 1996; Scientific American Magazine; by De Keersmaecker; 7 Page(s)

Over the past 2,000 years, the region that is now Belgium has been one of the most heavily trafficked crossroads of Europe. In 57 B.C. the territory, occupied by Celts, was invaded by the Romans and later by Normans. Throughout the centuries, a veritable parade of rulers came and went, including (after the Romans) the Merovingian Franks, the Germans, the Dutch, the Burgundians, the Austrians, the Spanish, the French and the Dutch again. From each of them came the threads, patterns and cloth that created the rich tapestry of Belgian culture, with its diverse contributions to art, cuisine and, not incidentally, brewing.

Some historians suspect that one of these subjugators, possibly the Romans, brought to the region a brewing process that may already have been ancient when it began flourishing around Brussels many centuries ago. During this process, brewers exposed their concoction to the air, causing it to be seeded (or, more accurately, inoculated) by whatever wild, wind-borne yeasts happened to drift in. Only within a roughly 500- square-kilometer area around Brussels and in the Payottenland, a valley of the Senne River on the west side of the city, did the right mix of airborne spores ensure that this spontaneous fermentation occurred consistently. Like Brussels itself, the brewing style thrived amid fields, orchards and woodlands and was nurtured by them.

Ring Bubbles of Dolphins; August 1996; Scientific American Magazine; by Marten, Shariff, Psarakos, White; 6 Page(s)

Below the towering cliffs of Makapuu Beach on the island of Oahu, Hawaii, is a unique laboratory dedicated to the study of dolphins. Project Delphis, run by the nonprofit conservation organization Earthtrust, in cooperation with Sea Life Park Hawaii, conducts research ranging from investigating dolphin self-awareness to exploring the animals¿ intelligence using an underwater computer touch screen. The scientists in the lab do not use food as a reward, so all the behavior observed is of the dolphins¿ own volition.

One of the most fascinating activities we have seen in our research involves no high-tech human toys at all. Instead the dolphins fashion their own entertainment by swirling the water with their fins and blowing bubbles into the resulting vortices to produce rings and helices of air. Furthermore, the physics behind the air rings turns out to be quite interesting. Few people doubt that dolphins are highly intelligent animals, but these observations demonstrate just how imaginative they can be.

Gaining on Fat; August 1996; Scientific American Magazine; by Gibbs; 7 Page(s)

Throughout most of human history, a wide girth has been viewed as a sign of health and prosperity. It seems both ironic and fitting, then, that corpulence now poses a growing threat to the health of many inhabitants of the richest nations. The measure of the hazard in the U.S. is well known: 59 percent of the adult population meets the current definition of clinical obesity, according to a 1995 report by the Institute of Medicine, easily qualifying the disease for epidemic status.

Epidemiologists at Harvard University conservatively estimate that treating obesity and the diabetes, heart disease, high blood pressure and gallstones caused by it rang up $45.8 billion in health care costs in 1990, the latest year studied. Indirect costs because of missed work pitched another $23 billion onto the pile. That year, a congressional committee calculated, Americans spent about $33 billion on weight-loss products and services. Yet roughly 300,000 men and women were sent early to their graves by the damaging effects of eating too much and moving too little.

The Amateur Scientist; August 1996; Scientific American Magazine; by Carlson; 3 Page(s)

There's a lot going on down among the microns. What we perceive as a rigid surface squashes easily under a finger's gentle pressure when viewed from a distance of a millionth of a meter. Increasing the temperature sends objects at that scale into even more violent upheavals.

Biological processes reshape many living things on this scale. For example, every beat of an insect's dorsal vessel--essentially, its heart--flexes its abdomen by a few microns.

Mathematical Recreations; August 1996; Scientific American Magazine; by Stewart; 3 Page(s)

Angela is standing in a room with perfectly reflecting walls. Somewhere in this Hall of Mirrors, her friend Bruno lights a match. No matter what the shape of the room or where the two are located, can Angela always look around and see Bruno¿s match or its reflection? Or equivalently, does the light from the match fill the whole room, not missing a single point--no matter where the match is placed?

This problem was first asked in print by Victor Klee in 1969, but its origins are thought to go back farther, at least to Ernst Straus in the 1950s. It comes in several variants. The room may be twoor three-dimensional (if the latter, then its floor and ceiling must also be mirrors). It may have flat walls--being polygons in two dimensions, polyhedrons in three--or curved walls. In all versions, the standard mathematical idealization replaces Angela¿s eye and Bruno¿s flame by points. These two points cannot lie on the room¿s boundaries; in addition, both are assumed to be transparent.

Reviews; August 1996; Scientific American Magazine; by Davis, Powell; 5 Page(s)

What distinguishes formerly classified digital satellite image archives from abstract art? As I gaze at my computer screen I can¿t always tell the difference. The line between art and scientific artifact has become a blur as cultural and scientific institutions move onto the Internet, suddenly sharing the same on-line formats and virtual architectures. In the process, the World Wide Web seems to be creating a broad definition of culture that forces us to recognize that science and art are parallel aspects of the same basic creative impulse rather than unrelated pursuits. It is revealing to examine how artists and art museums are using the Internet; they are particularly sensitive to aesthetic issues, and eventually the ability to express meaning visually will help determine whether the Web succeeds or fails as a new medium.

The on-line experience currently has some serious limitations. Anyone who has explored the Web will have no trouble thinking of the effort as trying to beat the clock. Depending on the capabilities of your computer, modem and network server, you will soon become acquainted with the inadequate pace of information delivery, especially for pictures, movies or sound.

Commentary: Wonders - Great Books and City Crops; August 1996; Scientific American Magazine; by Morrison, Morrison; 2 Page(s)

Cambridge, Massachusetts, is a long-urbanized, low-rise city of under 100,000, its population nearly constant for a century, with scant parkland or undeveloped lots. Gardens and lawns it has in plenty, but no one could point to a commercial farm. In 1995 one very successful local enterprise made surprising news, its agricultural technology at the highest level, its urban standing crop worth six figures in one indoor loft! Its 1/200th acre of deepgreen marijuana beds were of a strain pampered for generous yield of illicit resin, won (and then busted) under a phalanx of fluorescent tubes glowing behind closed doors and blanked windows.

Twenty years before this covert, postmodern agronomy, we had grown real grain crops in our own Cambridge garden open to New England rain and sun. We sowed only a few square feet of wheat, for our minute city harvest was intended not as an economic act but as an educational one. By sharing the old complex experiences of growing our daily bread, we hoped to grasp the metaphors brought so long ago to poetry and language out of the fields of grain.

Commentary: Connections - A lot of Boloney; August 1996; Scientific American Magazine; by Burke; 2 Page(s)

Ihave to confess a fatal weakness for Bologna, Italy. Apart from having one of the oldest universities in Europe, and possibly the most elegant women on the planet, it just so happens to be the food capital of the known universe. And after lunching on tortellini alla panna, you can go savor another work of mouthwatering precision: a giant brass meridian line, inlaid across the floor of the city¿s cathedral. Put there by Gian Domenico Cassini, the hottest astronomer around in 1668. Which was when his reputation brought him an offer he couldn¿t refuse, from Louis XIV¿s right-hand man, Jean-Baptiste Colbert: to run the new Paris observatory. Subsequently, he joined the great national effort there to determine the shape of the earth (which the French thought was not flattened at the poles).

Colbert needed to know such arcana so that the new navy he was putting together would more accurately be able to relate star-fix angles to positions on the planetary high seas (which would be different on an earth that was, or was not, flattened at the poles). This way, French ships would be able to navigate better. And rule the waves. And, perhaps, give the English one in the eye, by snitching the prime meridian from Greenwich and moving it to Paris. Unfortunately for amour-propre, they were wrong about the shape of the globe, which is why I¿m writing this in Greenwich mean time.

Working Knowledge; August 1996; Scientific American Magazine; by Heidel; 1 Page(s)

Casino revenues in the U.S. during 1994 totaled $17.5 billion. Of that, 65 percent was funneled as nickels, quarters and dollar bills through slot machines. These devices may qualify as the world¿s most user-friendly computers. The collection of springs, gears, levers and weights that the inventor Charles Fey cobbled together at the turn of the century to make the Liberty Bell, which became the model for the familiar threereel slot machine, has increasingly given way to a conglomeration of microprocessors and memory chips.

Each reel can stop at 22 positions (each one displaying various symbols, such as fruit, or simply a blank space), for a total of 10,648 different combinations. When slot machines were purely mechanical, the maximum odds of a payout were therefore 10,648 to one. But the heart of a contemporary slot machine is a microprocessor programmed to generate random numbers, which can be assigned to any combination on the reels. In effect, the microprocessor dictates what the machine will display--and pay. Because many or few random numbers can be assigned to any given combination, makers of slot machines can vary the odds as desired. For the top jackpot, the odds of pulling the single right combination may be set at 10 million to one.