The atomic theory has been of priceless value to chemists, but it has more than once happened in the history of science that a hypothesis, after having been useful in the discovery and the co-ordination of knowledge, has been abandoned Present position of the atomic theory. and replaced by one more in harmony with later discoveries. Some distinguished chemists have thought that this fate may be awaiting the atomic theory, and that in future chemists may be able to obtain all the guidance they need from the science of the transformations of energy. But modern discoveries in radioactivity[5] are in favour of the existence of the atom, although they lead to the belief that the atom is not so eternal and unchangeable a thing as Dalton and his predecessors imagined, and in fact, that the atom itself may be subject to that eternal law of growth and decay of which Lucretius speaks.
(F. H. Ne.)
[1] Robert Boyle, The Sceptical Chymist (1661); The Usefulness of Natural Philosophy (1663).
[2] Sir Isaac Newton, Principia, bk. ii. prop. 23.
[3] Freund, The Study of Chemical Composition.
[4] It will be seen that in the three gas diagrams of Dalton that are reproduced above, equal numbers of molecules are contained in equal volumes, but if Dalton held this view at one time he certainly afterwards abandoned it.
[5] Rutherford, Radioactivity.
ATONEMENT and DAY OF ATONEMENT. “Atone” (originally—see below—“at one”) and “atonement” terms ordinarily used as practically synonymous with satisfaction, reparation, compensation, with a view to reconciliation. As the English technical terms The religious doctrine. representing a theological doctrine which plays an important part not only in Christianity but in most religions, the underlying ideas require more detailed analysis. A doctrine of atonement makes the following presuppositions. (a) There is a natural relation between God and man in which God looks favourably upon man. (b) This relation has been disturbed so that God regards man’s character and conduct with disapproval, and inflicts suffering upon him by way of punishment. In the higher religions the disturbance is due, as just implied, to unsatisfactory conduct on man’s part, i.e. sin. (c) The normal relation may be restored, i.e. sin may be forgiven; and this restoration is the atonement.