而且，原子很小——确实很小。50万个原子排成一行还遮不住一根人的头发。以这样的比例，一个原子小得简直无法想像。不过，我们当然可以试一试。

　　Start with a line the length of a millimeter: 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.

　　先从1毫米着手，就是这么长的一根线：－。现在，我们来想像一下，这根线被分成了宽度相等的1000段。每一段的宽度是1微米。这就是微生物的大小。比如，一个标准的草履虫——一种单细胞的淡水小生物——大约为2微米宽，也就是0.002毫米，它确实小得不得了。要是你想用肉眼看到草履虫在一滴水里游，你非得把这滴水放大到12米宽。然而，要是你想看到同一滴水里的原子，你非得把这滴水放大到24公里宽。

　　原子

　　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.

　　换句话说，原子完全存在于另一种微小的尺度上。若要知道原子的大小，你就得拿起这类微米大小的东西，把它切成10000个更小的东西。那才是原子的大小：1毫米的千万分之一．这么小的东西远远超出了我们的想像范围。但是，只要记住，一个原子对于上述那条1毫米的线，相当于一张纸的厚度对于纽约帝国大厦的高度，它的大小你就有了个大致的概念。