How Does Aspirin Find a Headache?

by David Feldman

  When nitrous cellulose breaks down, nitric acid forms. Nitric acid attacks the proteins in the nail and turns the nail yellow. The yellowing occurs only on the top layers of the nail plate and will eventually fade away if more acids aren’t applied.

  2. Preservatives. Tolulene-sulfonimide and formaldehyde are part of the base coat of nail polishes and are used as preservatives. According to dermatologist Jerome Litt, of Beachwood, Ohio, formaldehyde resin can turn keratin (the tough, fibrous protein that is the principal constituent in nails) yellow.

  But don’t assume that yellow nails are necessarily caused by the chemicals in nail-care products (or other, noncosmetic chemicals, such as inks, shoe polishes, and dyes, which can also stain nails yellow). Many heavy smokers, for example, have yellow nails. Even the ingredients in some orally administered pharmaceuticals can stain nails.

  Physicians often examine fingernails to help determine the general health of patients, for many illnesses are betrayed by yellowing. The most common noncosmetics cause of yellowed nails is a yeast or other type of fungus infection underneath the nail plate. But many other, more serious illnesses can occasionally be diagnosed when a physician spots yellow nails, including diseases of the lymphatic system, thyroid, chronic respiratory disease, diabetes, and certain liver and kidney diseases.

  Other maladies are tipped off by different-colored nails. If the normal Caucasian nail looks pink, because of the ample blood supply to the nail bed underneath the nail plate, it can turn white when a person is anemic, and blue if the patient is suffering from heart or lung disease and insufficient oxygen is sent to the nail bed.

  Now that we’ve scared you sufficiently, we’ll remind you that nail polish is much more likely to cause the discoloration than the illnesses we’ve chronicled above.

  Submitted by Barbara Forsberg of Ballston Spa, New York.

  Why Are Most Corrugated Boxes from Japan Yellow?

  Unless it is bleached, the color of a box will be the color of its main material source—the wood that is turned into pulp fiber. In Japan (and China), the most plentiful source of fiber is straw, which has a yellow color, whereas North America’s main source for pulp is tannish trees.

  Robert H. Gray, vice-president of the corrugated division of Old Dominion Box Company, told Imponderables that demand for paper is so great that most countries turn to local fiber sources that can be “easily grown and harvested in volume.” Corrugated boxes often contain recycled fibers besides wood, and Japanese boxes tend to have a higher percentage of recycled material in their pulp, both for ecological reasons and because straw fibers are weaker than wood fibers and bond less effectively.

  As a result, the natural shade of Japanese boxes is more variable than our reliably colored kraft tan boxes. We don’t know whether the yellowish tinge of straw is what motivated Japanese boxmakers to dye their boxes yellow, but that is indeed what they do, as James F. Nolan, vice-president of the Fibre Box Association, explains:

  The paper used in Asia for corrugated boxes is primarily recycled—with highly mixed sources of waste paper. In order to provide a uniform color for good print quality, the paper for the outer sheet of the corrugated board must be dyed.

  Not that American boxes are beyond dye jobs. Although tan boxes are not dyed, liner-board white boxes are, according to Jim Boldt, of corrugated container giant Great Northern.

  One glimpse of what undyed paper might look like was supplied by Karl Torjussen, of Westvaco. He asked us if we could think of the color of the cardboard backing on legal pads. “Sure,” we responded, “sort of a dishwater gray.”

  That gray is the natural, undyed color of newsprint that has not been de-inked. No one cares too much what the back of a legal pad looks like, but we might find a stack of gray boxes utterly depressing—which is why, if boxes are made out of mostly recycled material, we dye them white and Asians dye them yellow.

  Submitted by Kirk Baird of Noblesville, Indiana.

  Why Are Covered Bridges Covered?

  We have driven by stretches of rivers where, it seemed, about every third bridge we passed was a covered bridge. Why is one covered when the next two are topless?

  The most obvious advantage to a covered bridge is that it blocks “the elements,” particularly snow. Accumulated snow can render a bridge impassable, and it is true that covered bridges are found most often in cold climates. Of course, one could argue that engineers should design covers for all roadways. But as we learned in Do Penguins Have Knees? (ah, but have we retained it?), bridges remain frozen long after adjacent road surfaces, primarily because bridge surfaces are exposed to the elements from all sides, the bottom as well as the top.

  But then some folks believe that covered wooden bridges were originally constructed to ease the fears of horses, who were skittish about crossing bridges, particularly if they saw torrents of water gushing below. The fact that covered bridges resembled wooden barns supposedly also allayed the horses’ anxiety.

  This question is reminiscent of one of our chestnut-Imponderables: Why do ranchers hang boots upside-down on fenceposts? The most likely answer is the same for both: to save wood from rotting. Alternate cycles of rain and sun play havoc on the wood. According to Stanley Gordon, of the Federal Highway Administration’s Bridge Division, an uncovered wooden bridge might last twenty years, while a covered bridge can last a century or longer.

  Submitted by Gary L. Horn of Sacramento, California. Thanks also to Matthew Huang of Rancho Palos Verdes, California.

  How Do Waiters and Waitresses Get Their Tip Money When the Gratuity Is Placed on a Credit Card?

  Let’s look at the life cycle of a credit card transaction at a restaurant:

  1. You get the bill. You pull out your trusty credit card and hand it to the waiter.

  2. In most restaurants, the waiter or other employee must authorize the charge. In all but small restaurants, this authorization is now done electronically, and increasingly, a “record of charge” is printed out automatically displaying the food, liquor, and tax charges. Some restaurants still use the old-fashioned “chit,” in which the amounts must be entered by pen.

  3. Conveniently (for the wait staff, anyway), a gaping space is left for “gratuity,” and the total amount of the bill is left empty.

  4. The waiter also puts his name or ID code on the record of charge (this is the strange, unidentifiable number often put in a box toward the bottom of credit card chits).

  5. If the charge has been approved, the waiter brings the paperwork back to the customer.

  This is the point at which many diners have no idea what to do. For some reason, the myth persists that waiters do not want you to charge their gratuity. Walter Sanders, director of corporate affairs for Citicorp Diners Club (Citicorp bought Diners Club in 1980), phrased the dilemma so charmingly that we are allowing him a blatant plug:

  My dad is one of those people so concerned about waiters and waitresses getting their tips that even when he charges a meal (on the Diners Club Card, of course) he still painstakingly digs for a cash tip, which he leaves under the coffee saucer.

  Well, your readers—and my dad—can now rest assured that waitpeople everywhere get their full tips, in cash, even when those tips are put on the Diners Club Card.

  6. Let’s assume the customer does pay the gratuity using a credit card. When the restaurant closes, the night’s proceeds are tabulated, and the waiter is paid on the spot, in cash (some restaurants pay on a weekly basis). The ID number of the waiter is used to identify his share of the gratuity money (although some restaurants pool tips). According to Melissa A. Bertelsen, of First Data Resources,

  most merchants have Electronic Data Capture devices that will allow the merchant to enter the amount of the ticket and tip. The device will then break out the tip by waiter number and total his amount in tips for the evening.

  7. Most credit card companies pay the merchant’s bank, electronically, the total amount charged, often within twenty-four hours. This quick transfer of mon
ey is one of the reasons why restaurateurs are willing to pay the “discount fee” that allows the credit card companies to make money. While it may take six weeks for the credit card company to be paid for the restaurant bill by the consumer, the restaurant is paid within a day or two. Thus the credit card issuer has to “eat” the float—the “free” use of the value of the charge—that the consumer has been granted.

  The negative float of credit card issuers, especially those, like American Express, that do not impose (high) finance charges for late payments by consumers, is one of their major costs of business. Nobody, especially you, is going to get rich by not having to pay a bill of fifty dollars for forty-five days, but imagine the impact of a financial institution contending with twenty million consumers receiving an interest-free loan for that period. Premium cards, such as American Express, try to regain the revenue lost in finance charges by pricing their cards higher than Visa or Mastercard, and by charging merchants a higher-percentage fee.

  If there is any reason why waiters might prefer cash, it might have to do with three letters—IRS. Obviously, tips put on credit cards leave a paper trail; increasingly, the IRS is trying to find ways to chase after undeclared income from workers who derive most of their money from tips.

  Submitted by Maria Scott of Cincinnati, Ohio.

  Why Do Beacons on Police Cars Flash Blue and Red Lights? Why Are the Blue Lights on the Passenger’s Side and the Red Lights on the Driver’s Side?

  Police work is serious business. We’ve always wondered why officers in fast pursuit of bad guys flash two-tone signals from their beacons. We called many big-city police departments to find out who their color consultant was.

  We quickly discovered that there is no national law specifying the colors on police car beacons. Yet in practice, the choices are few. A law enforcement information specialist at the National Criminal Justice Reference Library who wished to remain anonymous told Imponderables that at the time when red and blue lights were chosen for most police department beacons, high-intensity lights were not in use. So there was a practical advantage to using two colors—blue was easier to see during the day, and red was more clearly discerned at night.

  From time to time, there have been attempts to make yellow (the easiest color to observe from long distances) the official color of beacons throughout the United States, but the expense and effort of defying tradition and passing the legislation have killed such attempts. A federal regulation would cause disruptions in states like Pennsylvania, which have laws designating the color of beacons (in this case, blue and red for police). And opponents argue that yellow flashing lights would be confused with construction or street lights.

  Blue was probably chosen initially for its long association with police (e.g., blue lights in front of police stations, blue uniforms), and because of its high daylight visibility. And red has long been a symbol of warning and danger, and a signal to stop. Police departments in Los Angeles, Dallas, Detroit, Philadelphia, and Salt Lake City all use the red and blue beacons. Chicago and the Virginia State Police, on the other hand, have switched from red and blue to all-blue beacons.

  Several of the police officers we contacted argued that blue is the most effective color for beacons because no other emergency service uses it (both firefighters and ambulances use red beacons, and most construction and emergency transport cars employ yellow or amber). According to Bill Dwyer, of beacon manufacturer Federal Signal Corporation, big-city police departments, in particular, tend to prefer blue beacons, because the color distinguishes them from the many other emergency vehicles. And no other emergency vehicle features a two-colored beacon.

  Why is the red light on the driver’s side? We received the same answer from everyone, but Officer Romero, of the Los Angeles Police Department, put it best:

  The reason that the red light is over the driver’s seat is so that the driver being pursued can better see it. People are conditioned to stop for a red light; this is the most efficient way to signal the driver of a car in front of you to stop.

  A passenger in the offending car cannot see the red nearly as well as the blue light. The LAPD uses an amber light on the rear of the car, which is activated by an on-off switch. We are also conditioned to think of a yellow light as a caution light; in this case, cars behind the police vehicle are being cautioned by the amber lights to slow down because police activity is taking place.

  Police departments are constantly experimenting with color possibilities. The Virginia State Police experimented with blue lights for four years with equipment from six manufacturers before adopting them. Maryland tried a multicolor approach: Different colors hooked to switches controlled inside the car, with the intention of color-coding specific activities. In hot pursuit of a car, all-red might be appropriate; for a routine traffic ticket, red and blue might do the trick. And yellow would be the perfect understated fashion statement for lurking around a bend on a highway speed trap. But the state decided such color tactics were altogether too subtle and abandoned the idea.

  Submitted by Ronald Lindow of Pittsburgh, Pennsylvania. Thanks also to Jim Wright of New Orleans, Louisiana, and Sean O’Melveny of Littleton, Colorado.

  Why Is It So Hard to Find Single-Serving Cartons of Skim or Lowfat Milk? Why Is It So Hard to Find Single-Serving Cartons of Whole-Milk Chocolate Milk?

  Obviously, milk distributors do make single-serving sizes of lowfat milk and skim milk. They can be found in schools and institutions throughout the country. As Paul E. Hand, secretary and general manager of the Atlantic Dairy Cooperative reminded us, single-serving cartons of lowfat milk are a staple at McDonald’s, Burger King, and many other fast food establishments. Hand added that many school lunch programs do include prepackaged chocolate whole milk in one-cup cartons.

  So why can’t you find them in the supermarket? In some cases, you can. But grocery stores want to stock a limited number of container sizes and prefer selling big containers to small ones to maximize profits. (Note the demise of the seven-ounce soda bottle while three-liter containers proliferate on supermarket shelves.)

  Dairy distributors realize economies of scale by saving on packaging costs (obviously, four single-serving packages of milk are required to provide the milk in one quart container). Milk is a staple in most households, one used on a daily basis; Hand reports that there simply isn’t sufficient demand for single-serving cartons. If consumers bought them or demanded them in sufficient quantity, they’d be on the shelves.

  Prepackaged chocolate milk, an insignificant category two decades ago, while steadily gaining in market share, is still a stepchild to unflavored milks. In most cases, supermarkets don’t want to stock more than one type of chocolate milk. For example, Hershey, the closest to a national brand in this category, licenses local dairies to produce its brand of chocolate milk. Individual dairies can choose whether to use 2 percent or whole milk. According to Hershey Foods’ Carl Andrews, most local dairies will base their decision on whether to use whole or lowfat milk by assessing which type of unflavored milk sells better in their region.

  You live in southern California, Mitch, where 2 percent milk dwarfs the sale of whole milk. In many parts of the East coast of the United States, you’d have a hard time finding single-serving cartons of lowfat chocolate milk.

  Submitted by Mitch Hubbard of Rancho Palos Verdes, California.

  What Happens to the Ink When Newspapers Are Recycled?

  Before used newsprint can be recycled, it must be cleaned of contaminants, and ink is the most plentiful contaminant. The newsprint must be de-inked.

  Although synthetic inks are gaining market share, most newspapers still use oil-based inks. To clean the newspaper, the newsprint is chopped up and boiled in water with some additional chemicals until it turns into a slurry. As the fibers rub against each other, the ink rises to the surface, along with other nuisances, such as paper clips and staples. A slightly different, more complicated procedure is used to clean most newsprint with polymer-based inks. />
  Theodore Lustig, a professor at West Virginia University’s Perley Isaac Reed School of Journalism, and printing ink columnist for Graphic Arts Monthly, stresses that current technology is far from perfect:

  You should be aware that it is impossible to remove all ink from the slurry prior to recycling it into new paper. Since microparticles of ink remain, this would leave the paper rather gray if used without further processing. It is often subjected to bleaching or is mixed with virgin fibers to increase the finished recycled paper’s overall brightness, a requisite for readability contrast.

  More and more states are requiring publishers to use a higher proportion of recycled paper. As recyclers extract more ink from more newsprint, it may save trees in the forest, but it results in another ecological problem: what to do with unwanted ink. Although we may think of ink as a benign substance, the EPA thinks otherwise, a Lustig explains:

  The ink residue is collected and concentrated (i.e., the water is removed) into a sludge for disposition. However, since there are trace elements of heavy metals (lead, cadmium, chrome, arsenic, etc.) in this residue, this sludge is considered by EPA and other agencies to be a hazardous waste and has to be disposed of in accordance with current environmental laws.