If a substance is repeatedly subdivided, the result is what are known as "microscopic particles." These particles are distinguished from the solid mass which they originally formed by the size of the surface area per unit weight. This simple difference holds true down to a certain lower size limit, and when this limit is exceeded, a new state of matter is reached, in which the behavior of the particles is quite different to that of the original solid. Particles in this state are termed "superfine particles," and are distinct from ordinary particles. The size of the superfine particles, that...