I used to have a tee shirt, that had a picture of a garden mole and exterminator. The caption was "Mole problems? Call Avogadro 6.022 x 10^23."

It's a chemistry joke.

[rim shot]

OK, it's geeky. Avogadro's number is the number of atoms in a mole, which allows us to convert the unit of mass to number of atoms, and vice versa, by converting the atomic number to grams. Carbon 12 (the most common carbon isotope) is the reference--a mole of carbon 12 atoms will, in theory, mass exactly twelve grams. Similarly, a mole of hydrogen atoms will mass one gram.

Obviously, for this to work, we have to know pretty accurately just how many atoms there are in a mole. In fact, if we knew it accurately, and precisely enough, we could use it as an atomic basis for mass (just as the meter was defined in terms of wavelengths of a specific chemical laser, and more recently as the distance light goes in a certain time interval measured by a cesium clock). The current (crude) standard for mass is a lump of metal, a kilogram by definition, kept in a bell jar in Paris.

Recent research indicates that the traditional number, first identified by Avogadro, may be a little off. If they can refine the number sufficiently, it can be established as the basis for mass, and we can free ourselves of one of the few areas in which we're dependent on the duplicitous French...

Rand,
Hey, I had a t-shirt from that company. It said "Nothing exists except atoms and empty space. All else is opinion. -- Democritus, 460-370 BC"
I have lost the catalogue, and Web searches come up negative. Do you or any of your readers remember this wonderful t-shirt company? I don't remember its name but I do remember t-shirts that said things such as: "Reunite Gondwanaland!" and "If you are not part of the solution, you are part of the precipitant."

I think it was called Softwear. I might even still have the old catalog around. Unfortunately, Google reveals nothing.

Some years ago, I read an article in the Wall Street Journal (one of those first-page, center-column, off-beat stories), which described a potential crisis with the stability of the Standard Kilogram in Sevres, France. It seemed that somehow (I don't recall the details), suspicions had been raised that its mass was varying. At this point, the International Bureau of Weights of Measures had to turn to the universally acknowledged authority on the prototype Kilogram - an AMERICAN! Yes, they had to bring the American to France, where he brought together several of the individual subordinate national kilograms (including the American kilogram) in order to carry out the extremely delicate comparison to establish the continued validity of the "official" kilogram. So even though the duplicitous French are the custodians of the Prototype Kilogram, they had to call upon the help of an American to bail them out. As usual.