IN ANCIENT EGYPT THOSE who wanted a dazzling, white smile used a mixture of wine vinegar and pumice ground into a powder, sometimes with myrrh or powdered eggshells. This acidic and abrasive blend worked all too well, scouring away the enamel of the tooth itself as well as accumulated food and plaque. Prolonged use could expose the underlying layer of dentin, making the teeth more vulnerable to infection and decay.

TRACK STAR MICHAEL JOHNSON MAY NOT BE AWARE OF IT, BUT when he runs the 400-meter dash, he is covering exactly one hundredthousandth of the circumference of the planet. Well, not exactly. More than 200 years ago the men who created the metric system, some of the greatest scientific minds of Revolutionary France, called for a new unit of measurement, the meter, that would equal precisely one ten-millionth of the distance from the North Pole to the equator.

AFTER THE ENERGY CRISIS OF 1974, FRANCE embraced nuclear power as a route to energy independence. Today its 58 operating plants provide more than three-fourths of its electricity at much lower cost than in the United States. France has a single governmentowned utility, Electricité de France, whose nuclear installations were built by a single supplier, Framatome. These were originally standardized in two sizes, at 900 and 1,300 megawatts; recently a new size, 1,450 MW, has been added.

IT’S 1960 OR SO, AND YOU’RE A 12-YEAR -old living in a suburb somewhere on the East Coast. It’s late on a school night and you’re in bed, but you’re not sleeping; you’re listening to a big old Atwater Kent radio that you inherited when your mother got one of those new transistor radios for the kitchen. Tonight you’re tuned to WOR in New York at 710 AM, and you’re listening to this guy named Jean Shepherd who’s telling a funny story about when he was a kid and blew up his ham radio one day, scaring his mother and almost burning down the house.

BY THE END OF THE 1960S, ASTRONOMERS WERE FACED WITH increasing blindness. The largest telescope in the world was the 200-inch Hale Telescope on Mount Palomar in California. Since its dedication in 1948, suburban sprawl, with the accompanying light pollution, had made observations increasingly difficult. Moreover, with interest in space science and astrophysics growing enormously, demand for telescope time had far outrun the available supply.

IN THE EARLY 1930S, DEEP WITHIN THE STEEP, ROCKY SLOPES OF Utah’s Oquirrh Mountains, the Utah Copper Company reached a strange milestone. For almost 30 years the company’s giant power shovels had been eating away at a massive mountain of low-grade copper ore that lay at the head of narrow Bingham Canyon.

THE DARK EMPTINESS BEYOND PLUTO, THE FARTHEST planet in our solar system, defies comprehension. The sun is little more than a bright star in that void, Earth lost in its feeble glare. Yet even out there, there’s a little piece of Earth. Almost seven billion miles from home, faithfully calling back to a planet that has almost forgotten it exists, is humankind’s oldest functioning spacecraft, Pioneer 10.

TOM ZOELLNER’S ARTICLE ON THE DE velopment of offshore drilling (“Oil and Water,” Fall 2000) brought back some exciting memories. In 1950 I was one of a small team of geologists working for Magnolia Petroleum out of Morgan City, Louisiana, and it was my good fortune to be present the day we discovered oil on our drill site 25 miles offshore. We ran a routine Schlumberger electric log, and it showed a thick sand unit that looked hydrocarbon-saturated.

THE ART OF MAKING cheese is thousands of years old, but the food most Americans have grown up calling cheese is a twentieth-century invention. A hundred years ago, America lagged far behind Europe in cheese consumption. Dairy scientists and U.S. Department of Agriculture (USDA) officials resolved to do something about it. The problem, they believed, was the erratic nature of domestic cheese. Even a master cheese-maker couldn’t consistently produce batch after batch of top quality.

MAJ. WILLIAM (“PETE”) KNIGHT WAS in trouble, and he didn’t even know it. It was October 3,1967, and he had just set a world aircraft speed record of Mach 6.7 (6.7 times the speed of sound, or 4,520 mph) in a specially modified X-15 research plane flying at an altitude of 102,000 feet. As Knight approached the dry bed of Rogers Lake, at Edwards Flight Test Center in the Southern California desert, he found himself coming in fast and heavy.

SINCE ANCIENT TIMES , fingerprints have been recognized as a definitive means of establishing who someone is. Unlike faces, handwriting, or other characteristics, they are unique to each person and cannot be imitated. They do not change over time, and despite the attempts of criminals to efface their prints with sandpaper, acid, or surgery, they cannot be disguised or permanently altered.

ALMOST EVERY WAR IN AMERICAN HISTORY HAS inspired valuable innovations in military technology. The Civil War, for example, saw the first major use in the United States of rapid-fire weapons, land and naval mines, observation balloons, and ironclad ships, among other inventions. One of the most farsighted (if impractical) schemes of that conflict was devised in 1862 by an Indianapolis machine-shop owner named Albert E. Redstone. He proposed to build an armorclad, steam-operated “engine of war”—what today would be called a tank.

The Creation Of The Inkjet

REGARDING THE ARTICLE “Printing Enters the Jet Age,” in your Spring 2001 issue (by Thomas Kraemer), your readers should know that the business of designing and building inkjet print heads has always been a team effort from start to finish and remains so to this day.

REGARDING THE ARTICLE “Printing Enters the Jet Age,” in your Spring 2001 issue (by Thomas Kraemer), your readers should know that the business of designing and building inkjet print heads has always been a team effort from start to finish and remains so to this day.

YOU TAKE THE U.S. 380 EXIT EAST OFF I-25 AT TINY SAN Antonio, New Mexico, heading for the Rio Grande. Conrad Hilton was born in San Antonio, and his father ran the first Hilton hotel in an adobe building near the train station. Now the hottest place in San Antonio is the Owl Bar & Café, regionally famous for selling “the world’s best green chili cheeseburger.”

INCORPORATING SUCH UP-TO-THE- minute technologies as microprocessor control, solid-state electronics, data radio, and a tilting mechanism that banks them around curves, the new 150 mph Acela Express trains on Amtrak’s Washington-New York-Boston Northeast Corridor surely represent cutting-edge transportation for the twenty-first century. But these newest of trains travel over a civil engineer- ing infrastructure that owes much to the skills and foresight of engineers of the very early twentieth, and even the nineteenth, century.

YOUR ARTICLE “THE BIGGEST MINE ,” by Timothy J. LeCain (Winter 2001), reminds me of a personal story. In June 1967, as a young civilian engineer working for the Army, I had to travel to Tooele Army Depot in Utah to conduct some tests. One day when we had an errand to run in Salt Lake City, the locals in Tooele recommended that we stop at the Kennecott Copper Mine in the mountains and take a look at the big hole there. The claim at the time was that you could put the Empire State Building in the bottom and look down on it.

THE WORLD’S FIRST HYDROGEN BOMB, DESIGNATED MIKE , exploded on November 1, 1952. The test took place on a Pacific island named Elugelab, which ceased to exist within a second of detonation. Mike’s fireball spread fast enough to terrify people 30 miles away who had seen previous nuclear tests. One scientist later described it as “so huge, so brutal—as if things had gone too far.

SINCE ITS ESTABLISHMENT IN 1982, THE CHEMICAL Heritage Foundation (CHF) has been a focus for efforts in both industry and academia to preserve “the treasures of the chemical and molecular community.” In June CHF inaugurated its new, permanent home in Philadelphia. The complex includes the Donald F. and Mildred Topp Othmer Library of Chemical History as well as the Arnold and Mabel Beckman Center for the History of Chemistry, both named for couples long prominent in chemical research and history.