are in astronomy, or the millionth part of a second, as they often are in physics. Let me here endeavour to set forth some of the results at which natural philosophers have arrived with regard to the ultimate constitution of matter.
Take a lump of loaf sugar and crush it in a mortar, each of the fragments is, of course, a particle of sugar still. Let the operation of grinding be carried on until the entire lump has been reduced to powder of the utmost fineness, which any grinding apparatus is capable of effecting. Each of the minute particles is still, nevertheless, a fragment possessing the attributes and properties of sugar. It has the sweetness and the hardness, the solubility and the chemical composition of the original lump. There is a difference in dimensions, but no difference of any other kind. But now let us suppose that we were in possession of some pulverising apparatus which would permit the reduction of the sugar to be carried on to an extent far greater than that which could be obtained by the most perfect grinding-mill known to the mechanic. The sugar might be comminuted by such agency to so great an extent that the little particles into which it had become transformed could only be discerned as the smallest of specks under the most potent of microscopes. We have the best reasons for knowing that even these little specks, which are of such extreme minuteness that the original lump contained many millions of them, are still, neither more nor less than sugar.
Up to the present stage the reduction has not transformed, so to speak, the actual nature of the material submitted to the treatment. Though the particles have been crumbled to such an extent that after any further
