diminution they would cease to be visible, even in the microscope, yet we can, at all events, conceive that further disintegration could be carried on. In fact, the very smallest of these grains, only just visible under the microscope, might be crushed into a thousand parts, and still each little part would not yet have lost the attributes which belonged to sugar. We have now arrived at the conception of a magnitude too small to affect any of our senses, no matter how they may be fortified by the aid of instruments. But the trituration may be conceived to be carried on one step further, until, at last, the original lump has been reduced to particles of sugar so small as to admit of no further subdivision without a total transformation in character. This is an extremely important point. It may, in fact, be regarded as one of those cardinal doctrines which it has been the glory of modern science to teach. There was a time when it was believed that the subdivision of a particle of sugar might be carried on indefinitely. We now know that is not the case. We know there is a certain portion so small that it cannot be again divided. I do not mean that this particle is not in itself composed of separate objects, but what I do mean is, that if, when we have an ultimate particle of sugar, it were divided into two parts, as it might be by chemical processes, neither of those two parts would be sugar or anything like sugar. They would each be something which possessed neither the hardness, nor the colour, nor the sweetness, nor, indeed, any of the attributes characteristic of the original material.
This same argument may be applied to every other substance besides that which I have taken as a first illustration. The atmosphere, composed as it is of oxygen
