When Do Fish Sleep? Part 16

D.

Cleveland

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E.

Richmond

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F.

Atlanta

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G.

Chicago

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H.

St. Louis

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I.

Minneapolis

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J.

Kansas City

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K.

Dallas

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L.

San Francisco The star note enables the treasury to issue a new set of serial numbers rather than attempting to rea.s.sign all the missing serial numbers of defective notes. On U.S. notes, a star subst.i.tutes for the prefix letter. A replacement U.S. note might look like this: 00000007 B. On Federal Reserve notes, a star subst.i.tutes for the letter at the end of the serial number, so that the location of the Federal Reserve district is kept intact: D 00000007 .

William Bischoff, a.s.sociate curator of the American Numismatic Society, adds that there is one other use for the star note. The Bureau of Printing and Engraving uses printers with eight-digit numbering cylinders to produce one hundred million notes at a time. But for the one-hundred-millionth note, a ninth digit is needed. Rather than bothering to add another digit on the cylinder that would literally be used on one out of a hundred million notes, the one-hundred-millionth note is a hand-inserted star note.

To What Do the Numbers a.s.signed to Automotive Oil Refer?

Thirty years ago, 10-30 was considered a premium automotive oil. Today, one can buy 10-50 or even 10-60 oil, but few people know what these numbers mean.

The numbers measure the viscosity of the oil. The higher the number, the higher the viscosity (meaning the oil is less likely to flow). Although the viscosity of a liquid is not always directly correlated to thickness, high-viscosity oils are thicker than their low-viscosity counterparts.

The numbers on engine and transmission oils are a.s.signed by the Society of Automotive Engineers. Their numbers range from 5W to 60. The W stands for winter. When a W follows a number, it indicates the viscosity of the oil at a low temperature. When there is no W following a number, the viscosity is measured at a high temperature.

All oil companies promote multigrade oils, which are designed to perform well in hot or cold temperatures. Thus 10W-40 doesn't indicate a range of viscosity, but rather the low viscosity of oil during winter (when one desires greater flow capabilities) and high viscosity in the summer.

Submitted by Tom and Marcia Bova of Rochester, New York.

When I Put One Slice of Bread in My Toaster, the Heating Element in the Adjacent Slot Heats Up as Well. So Why Does My Toaster Specify Which Slot to Place the Bread in If I Am Toasting Only One Slice?

Considering that the pop-up toaster has proven to be perhaps the most durable and dependable kitchen appliance, we were surprised to learn that toasting technology varies considerably from model to model. The earliest toasters browned one side of bread at a time; one had to decide when to flip the bread over by hand, a problem not unlike the momentous decision of when to flip over a frying pancake or hamburger.

Now that even the simplest pop-up toaster has a toast selector dial to allow the user to choose the preferred degree of doneness, most of the guesswork in toasting has been eliminated. We are not even allowed to select which of two or four slots to put in our one meager slice of bread. Why not?

Actually, nothing dire will result if you don't use the slot marked ONE SLICE. The worst that will happen is that the toaster will pop up an underdone or overdone piece. But why is the same well that manages to produce wonderful toast when it has company next door suddenly rendered incompetent when forced to work alone?

The answer depends upon the type of technology the toaster uses to determine doneness. The simplest toasters, now pa.s.se, worked from a simple time principle. The darker the brownness dial was set for, the longer the timer set for the toaster to heat the bread. Toasters that worked on a timer alone did not need a ONE SLICE notation because they always cooked the bread for the same amount of time, as long as the brownness dial wasn't changed. Using a timer alone guaranteed that a second set of toast would come out overdone, because the toaster was already warmed up yet toasted the second set for the same period of time as the first batch that was heated from a "cold start."

To solve the problem, appliancemakers inserted a thermostatic switch in toasters, which measured the heat of the toaster rather than the time elapsed in cooking. The thermostat alone caused a reverse problem. A second batch of bread would come out underdone because the first cycle had already caused the heating element to charge. The toaster didn't "know" that the second batch of bread hadn't been exposed to the toaster long enough; it knew only that the toaster had achieved the desired temperature.

The solution to the problem was to use a combination timer-thermostat. Today, the timer is not set off until the thermostat tells the timer that the toaster has reached the preset temperature (determined by the setting of the brownness dial). With this technology, it might take a minute for the thermostat to tell the timer to start ticking with the first set of toast but only a few seconds for the second or third.

We spoke to an engineer at Proctor-Silex who told us that most of their toasters have the thermostat close to-or in some cases, inside-the well that is marked ONE SLICE so the thermostat can do a more accurate job of "reading" the correct temperature for that slice. Some toasters that have ONE SLICE markings are "energy saver" toasters, specifically designed so that the heating element in the second slot will not be charged if it does not contain bread.

Sunbeam has long produced the 20030 toaster, an elegant two-slicer that selects the proper brownness of the bread by a radiant control that "reads" the surface of the bread to determine the degree of doneness. As far as we know, the Sunbeam 20030 is the only toaster that doesn't work on a time principle. The 20030 actually measures the surface temperature of the bread by determining its moisture level and can accurately measure the time needed to toast any type of bread. Wayne R. Smith, of Sunbeam Public Relations, told Imponderables, "There's no point in having radiant controls in both slots when having a control in one slot works just as well."

Submitted by Lisa M. Giordano of Tenafly, New Jersey. Thanks also to Muriel S. Marschke of Katonah, New York; and Jim Francis of Seattle, Washington.

Why Are Almost All Cameras Black?

Black isn't the most obvious color we would pick for cameras. Not only is black an austere and a threateningly high-tech color to amateurs, it would seem to have a practical disadvantage. As Jim Zuckerman, of a.s.sociated Photographers International, explained, black tends to absorb heat more than lighter colors, and heat is the enemy of film.

Of course, there was and is no reason why the exteriors of cameras need to be black. For a while, chromium finishes were popular on 35 millimeter cameras, but professional photographers put black tape over the finish to kill any possible reflections. Sure, some companies now market inexpensive cameras with decorator colors on the exterior. Truth be told, the persistence of black exteriors on cameras has more to do with marketing than anything else. As Tom Dufficy, of the National a.s.sociation of Photographic Manufacturers, told us: "To the public, black equals professional."

Submitted by Herbert Kraut of Forest Hills, New York.

Why Is There a Permanent Press Setting on Irons?

We buy a permanent press shirt so that we won't have to iron it. Then after we wash the shirt for the first time, it comes out of the dryer with wrinkles. Disgusted, we pull out our iron only to find that it has a permanent-press setting. Are iron manufacturers bribing clothiers to renege on their promises? Is this a Communist plot?

The appliance industry is evidently willing to acknowledge what the clothing industry is reluctant to admit: A garment is usually permanently pressed only until you've worn it-once. Wayne R.Smith, consultant in Public Relations to the Sunbeam Appliance Company, suggested that "permanent press" was chosen to describe the benefits of some synthetic materials because "it has a far more attractive sound to consumers than 'wrinkle-resistant.'"

We know what Mr. Smith means. We've always felt that the difference between a water-resistant watch and a waterproof watch was that the waterproof one would die the moment after it hit H2O.

What Causes Double-Yolk Eggs? Why Do Egg Yolks Sometimes Have Red Spots on Them?

Female chicks are born with a fully formed ovary containing several thousand tiny ova, which form in a cl.u.s.ter like grapes. A follicle-stimulating hormone in the bloodstream develops these ova, which will eventually become egg yolks. When the ova are ripe, the follicle ruptures and an ovum is released. Usually when a chicken ovulates, one yolk at a time is released and travels down the oviduct, where it will acquire a surrounding white membrane and sh.e.l.l.

But occasionally two yolks are released at the same time. Double-yolk eggs are no more planned than human twins. But some chickens are more likely to lay double-yolk eggs. Very young and very old chickens are most likely to lay double yolks; young ones because they don't have their laying cycles synchronized, and old ones because, generally speaking, the older the chicken, the larger the egg she will lay. And for some reason, extra-large and jumbo eggs are most subject to double yolks.

If a chicken is startled during egg formation, small blood vessels in the wall may rupture, producing in the yolk blood spots-tiny flecks of blood. Most eggs with blood spots are removed when eggs are graded, although they are perfectly safe to eat.

Submitted by Lewis Conn of San Jose, California. Thanks also to Melody L. Love of Denver, North Carolina.