BRADFORD PARKINSON SOMETIMES CARRIES AROUND A photograph of a specially equipped tractor. The machine is equipped with a robotic driver that navigates back and forth solely on signals from the Global Positioning System, the network of 24 satellites orbiting 11,000 miles above Earth that beams precisely timed signals to allow anyone with a GPS receiver to pinpoint exactly where he is.

INSECTS LOVE US. TERMITES ARE CONNOISSEURS OF THE wood we use in construction, each year munching through $3 billion worth. Fleas, ticks (which are not insects, strictly speaking), biting flies, and disease-vectoring mosquitoes are blood-loving little vampires in search of warm, carbon dioxide-exhaling bodies to dine on. Housefleases they transmit is big Every year more than a billion pounds of pesticide, with active ingredients worth $8.5 billion, changes hands in the United States.

THE BRONX-WHITESTONE Bridge has long been New York City’s least charismatic major span. One reason is that it connects two resolutely untrendy boroughs, the Bronx and Queens. But another reason is the way it has repeatedly been strapped in and buckled up for safety through the years. Underneath it all lies a beautiful bridge, but the effect has been like dressing Heidi Klum in a snorkel coat and galoshes. Now, however, the bridge is being stripped down to something resembling its original designer attire.

IF YOU WANTED TO BUILD A BASEBALL PITCHING MACHINE and had never seen one, how would you do it? By analogy, you would probably use some sort of mechanical arm. If that didn’t work, you might try a sharp impact with a piston, or perhaps some sort of slingshot. But when Charles Hinton, a mathematics instructor at Princeton University in the mid-1890s, saw his school’s pitchers getting sore arms from throwing too much batting practice, he came up with a more imaginative solution.

BRADFORD PARKINSON REMEMBERS HOW HARD IT WAS. He went to Capitol Hill again and again to ask members of Congress to support an ambitious science project proposed by the National Aeronautics and Space Administration. The project is fairly well known today. It’s Gravity Probe B, launched last spring in an audacious attempt to get an exquisitely accurate measurement of the curvature of space-time predicted by Albert Einstein. Any deviation from Einstein’s theory may point toward unexplored areas of physics. Is that mind-blowing, or what?

AT 5:00 A.M. ON JANUARY 16, 1966, CAPT. CHARLES Wendorf, a 29-year-old U.S. Air Force pilot, sped his B-52 bomber down the dark runway at Seymour Johnson Air Force Base in North Carolina. Over the next day or so, Wendorf and the six airmen sharing his plane planned to fly over the Atlantic, cross Europe, brush the Eastern Bloc, then turn around and come home. Presumably they would make it back to the States without releasing their cargo: four hydrogen bombs.

THE ARTICLE ON BAT guano in the Spring 2004 issue (“High Wire,” by Rockey Spicer) reminded me of an important aerospace use for the stuff. Back in pre- and post- Sputnik days I worked for the Raymond Engineering Laboratories, in Middletown, Connecticut. Because of our skill with explosive actuators, we received a contract to design and build explosively erected antennas for the Mercury, and later Gemini, spacecraft.

Dung In The Space Race

THE ARTICLE ON BAT guano in the Spring 2004 issue (“High Wire,” by Rockey Spicer) reminded me of an important aerospace use for the stuff. Back in pre- and post- Sputnik days I worked for the Raymond Engineering Laboratories, in Middletown, Connecticut. Because of our skill with explosive actuators, we received a contract to design and build explosively erected antennas for the Mercury, and later Gemini, spacecraft.

I READ WITH GREAT INTER est Frederic D. Schwarz’s article about the oldest talkie (“Notes From the Field,” Spring 2003), which described the world’s oldest film with synchronized sound, recorded in Thomas Edison’s laboratory. It was fascinating, but I was sorry to reach the end of the article without finding the answer to a question that has puzzled me for several years: What piece was the violinist playing?

ABOUT 10 YEARS AGO a long-forgotten genre of popular instrumental music—full of gimmicky stereo effects and heavy on theremins, synthesizers, and similar otherworldly sounds —was dug up from the oblivion it had long inhabited and revived for today’s reflexively ironic youth under the name Space-Age Bachelor Pad Music.

MY THANKS TO TOM HUNT ington for “The Gimmick That Ate Hollywood,” which made the Spring 2003 issue a definite keeper. Those of us in the business the article is about have a saying, “3-D is the wave of the future—and always will be.”

IN THE NINETEENTH CENTURY THERE WAS NO EASY WAY TO heat water. People generally used cookstoves to do it, but first they had to chop wood or lift heavy hods of coal, and then they had to kindle the fuel and stoke the fire. In cities the wealthy heated their water with gas made from coal, but it didn’t burn clean, the heater had to be lit every time they wanted hot water, and if they forgot to extinguish the flame, the tank could blow up. Moreover, in many areas wood or coal or coal gas was expensive and hard to find.

ON FEBRUARY 10, 2003, with government intelligence agencies indicating a high risk of terrorist attacks, the Department of Homeland Security advised Americans to prepare by keeping emergency supplies on hand. The requisites included food and water, a first-aid kit, and, in case of a biological or chemical attack, plastic sheeting and duct tape.

THE MOST DRAMATIC MOMENT DURING THE DETROIT auto show in January 2003 occurred at the Detroit Opera House. General Motors spent almost a million dollars turning the hall into a cocktail lounge and showroom and then used it to unveil its most audacious concept car in many years, the Cadillac Sixteen. A clear homage to the most glamorous automobiles of the 1920s and 1930s, the Sixteen includes a champagne refrigerator and a crystal Bulgari clock, but that’s not what caught everyone’s attention.

THOUGH QUITE INFORMA tive, Mr. Huntington’s piece contains a fundamental technical error in its explanation of anaglyphic stereography. It states that “in this system. … one [image] is projected through a red filter, making it invisible to the eye wearing the green lens, while the other is projected through a green filter, making it invisible to the eye wearing the red lens.” In fact the process works the opposite way.

I COMMEND BRIDGET Mintz Testa for her excellent article “Mission Control” (Spring 2003). You might like to know that there was also a second real-time computer facility during the Apollo program, in addition to Mission Control’s Real Time Computer Complex (RTCC). The Real Time Auxiliary Computing Complex (RTACC), located in the other wing of Building 30, was staffed by NASA and TRW engineers, and it performed computations for trajectory, mass properties, solar radiation, extravehicular-activity heat load, and numerous other matters.

I LOVED YOUR “POSTFIX” column about “windwashers” (by Arthur G. Sharp, Fall 2002). I am an 87-year-old former Seabee who was put ashore on Eniwetok Island in April 1944. I was promoted to stevedore, and our small group unloaded shiploads of supplies onto the island. Our work was quite dirty, the temperature sometimes reached 120 degrees, and fresh water was at a premium. We didn’t relish washing with saltwater.

THANK YOU, KEN ALDER , for “The Mis-Measure of All Things” (Fall 2002). This is a town that makes millions of gears and chains for the front-wheel drives of cars around the world, mostly metric but a mixed bag. The worst thing about converting to metric was what happened when the wine and liquor industry shifted. The half-gallon became 1.75 liters, but the price stayed the same—for almost 8 percent less. Beer stayed with the old system, as did surveyors and real estate. Try selling an acre in square meters.

After seeing the first Charlie’s Angels movie, a friend of ours gave the following capsule review: “They should have had fewer fights and blown more stuff up.” Readers with similar tastes will love implosionworld.com , a Web site that covers the demolition industry with news articles, reminis

IN THE MIDDLE OF THE NINETEENTH CENTURY, WESTERN civilization was at the peak of its early intoxication with railroads. Everywhere dreamers were bent over maps, drawing lines. Walt Whitman wrote: