A short history of nearly everything - Bill Bryson [66]
Above all, atoms are tiny—very tiny indeed. Half a million of them lined up shoulder to shoulder could hide behind a human hair. On such a scale an individual atom is essentially impossible to imagine, but we can of course try.
Start with a millimeter, which is a line this long: -. Now imagine that line divided into a thousand equal widths. Each of those widths is a micron. This is the scale of microorganisms. A typical paramecium, for instance, is about two microns wide, 0.002 millimeters, which is really very small. If you wanted to see with your naked eye a paramecium swimming in a drop of water, you would have to enlarge the drop until it was some forty feet across. However, if you wanted to see the atoms in the same drop, you would have to make the drop fifteen miles across.
Atoms, in other words, exist on a scale of minuteness of another order altogether. To get down to the scale of atoms, you would need to take each one of those micron slices and shave it into ten thousand finer widths. That's the scale of an atom: one ten-millionth of a millimeter. It is a degree of slenderness way beyond the capacity of our imaginations, but you can get some idea of the proportions if you bear in mind that one atom is to the width of a millimeter line as the thickness of a sheet of paper is to the height of the Empire State Building.
It is of course the abundance and extreme durability of atoms that makes them so useful, and the tininess that makes them so hard to detect and understand. The realization that atoms are these three things—small, numerous, practically indestructible—and that all things are made from them first occurred not to Antoine-Laurent Lavoisier, as you might expect, or even to Henry Cavendish or Humphry Davy, but rather to a spare and lightly educated English Quaker named John Dalton, whom we first encountered in the chapter on chemistry.
Dalton was born in 1766 on the edge of the Lake District near Cockermouth to a family of poor but devout Quaker weavers. (Four years later the poet William Wordsworth would also join the world at Cockermouth.) He was an exceptionally bright student—so very bright indeed that at the improbably youthful age of twelve he was put in charge of the local Quaker school. This perhaps says as much about the school as about Dalton's precocity, but perhaps not: we know from his diaries that at about this time he was reading Newton's Principia in the original Latin and other works of a similarly challenging nature. At fifteen, still schoolmastering, he took a job in the nearby town of Kendal, and a decade after that he moved to Manchester, scarcely stirring from there for the remaining fifty years of his life. In Manchester he became something of an intellectual whirlwind, producing books and papers on subjects ranging from meteorology to grammar. Color blindness, a condition from which he suffered, was for a long time called Daltonism because of his studies. But it was a plump book called A New System of Chemical Philosophy, published in 1808, that established his reputation.
There, in a short chapter of just five pages (out of the book's more than nine hundred), people of learning first encountered atoms in something approaching their modern conception. Dalton's simple insight was that at the root of all matter are exceedingly tiny, irreducible particles. “We might as well attempt to introduce a new planet into the solar system or annihilate one already in existence, as to create or destroy a particle of hydrogen,” he wrote.
Neither the idea of atoms nor the term itself was exactly new. Both had been developed by the ancient Greeks. Dalton's contribution was to consider the relative sizes and characters of these atoms and how