Modern scientific ideas : especially in the idea of discontinuity / by Sir Oliver Lodge, F.R.S.

  • Oliver Lodge
Date:
1927
Catalogue details

Licence: In copyright

Credit: Modern scientific ideas : especially in the idea of discontinuity / by Sir Oliver Lodge, F.R.S. Source: Wellcome Collection.

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    which constitute a drop of water, because they are so excessively small and numerous that our senses, even when aided with the most powerful microscope, cannot detect any breach of continuity; the individual atoms are beyond our sense perception. Yet they have been counted, and their size is known. The number of atoms in a thimbleful of water is enormous, about the same number as the grass blades on the entire earth. It seems at first rather wonder¬ ful that they can be counted at all. So also it may seem difficult to estimate the number of grains of sand on a sea beach; but there is no real difficulty in making an estimate of that number, provided we know how many miles the beach is long, how many yards it is broad, and how many feet it is on the average deep. For we have only to estimate the number of cubic inches and then to count the grains of sand in, say, a tenth of one cubic inch —a thing which a child would be able to do. Scientific men are willing to take any amount of trouble to comprehend and express the facts of nature; and thus they have become able to specify the number of atoms in the whole earth, or, indeed, in the solar system, or any other mass of matter, however big. But it may be said, How do we know that matter is atomic at all? How do we know that atoms exist if we never see them? How can we be sure that water is not really continuous? On that subject there has been much speculation since ancient times, but our knowledge of it became definite and metrical during the nineteenth century. The arguments for the existence of atoms—that is, of some units in matter which can be counted, as we might count the pips in an apple or the bees in a swarm —began to be cogent from certain facts in chemistry, dis¬ covered and formulated mainly by John Dalton at the beginning of the nineteenth century. He found that the chemical elements entered into combination in a perfectly definite numerical way; that when, for instance, hydrogen and oxygen combined to form water they did not com¬ bine haphazard, but that eight parts of oxygen, by weight, combined with each single part of hydrogen. And,