pp. 537-587.

[5] Or perhaps an isotope of helium (see below).

As concerns the spontaneous transmutations undergone by the radioactive elements, the facts appear to indicate (or, at least, can be brought into some sort of order by supposing) the atom to consist of a central nucleus and an outer shell, as suggested by Sir Ernest Rutherford. The nucleus may be compared to the sun of a solar system. It is excessively small, but in it the mass of the atom is almost entirely concentrated. It is positively charged, the charge being neutralised by that of the free electrons which revolve like planets about it, and which by their orbits account for the volume of the atom. The atomic weight of the element depends upon the central sun; but the chemical properties of the element are determined by the number of electrons in the shell; this number is the same as that representing the position of the element in the periodic system. Radioactive change originates in the atomic nucleus. The expulsion of an α-particle therefrom decreases the atomic weight by 4 units, necessitates (since the α-particle carries two positive charges) the removal of two electrons from the shell in order to maintain electrical neutrality, and hence changes the chemical nature of the body, transmuting the element into one occupying a position two places to the left in the periodic system (for example, the change of radium into niton). But radioactivity sometimes results in the expulsion of a β-particle from the nucleus. This results in the addition of an electron to the shell, and hence changes the chemical character of the element, transmuting it into one occupying a position one place to the right in the periodic system, but without altering its atomic weight. Consequently, the expulsion of one α- and two β-particles from the nucleus, whilst decreasing the atomic weight of the element by 4, leaves the number of electrons in the shell, and thus the chemical properties of the element, unaltered. These remarkable conclusions are amply borne out by the facts, and the discovery of elements (called “isobares”) having the same atomic weight but different chemical properties, and of those (called “isotopes”) having identical chemical characters but different atomic weights, must be regarded as one of the most significant and important discoveries of recent years. Some further reference to this theory will be found in §§ 77 and 81: the reader who wishes to follow the matter further should consult the fourth edition of Professor Frederick Soddy’s The Interpretation of Radium (1920), and the two chapters on the subject in his Science and Life (1920), one of which is a popular exposition and the other a more technical one.

These advances in knowledge all point to the possibility of effecting transmutations at will, but so far attempts to achieve this, as I have already indicated, cannot be regarded as altogether satisfactory. Several methods of making gold, or rather elements chemically identical with gold, once the method of controlling radioactive change is discovered (as assuredly it will be) are suggested by Sir Ernest Rutherford’s theory of the nuclear atom. Thus, the expulsion of two α-particles from bismuth or one from thallium would yield the required result. Or lead could be converted into mercury by the expulsion of one α-particle, and this into thallium by the expulsion of one β-particle, yielding gold by the further expulsion of an α-particle. But, as Professor Soddy remarks in his Science and Life just referred to, “if man ever achieves this further control over Nature, it is quite certain that the last thing he would want to do would be to turn lead or mercury into gold—for the sake of gold. The energy that would be liberated, if the control of these sub-atomic processes were as possible as is the control of ordinary chemical changes, such as combustion, would far exceed in importance and value the gold. Rather it would pay to transmute gold into silver or some base metal.”

In § 101 of the book I suggest that the question of the effect on the world of finance of the discovery of an inexpensive method of transmuting base metal into gold on a large scale is one that should appeal to a novelist specially gifted with imagination. Since the words were first written a work has appeared in which something approximating to what was suggested has been attempted and very admirably achieved. My reference is to Mr. H. G. Wells’s novel, The World Set Free, published in 1914.

In conclusion I should like to thank the very many reviewers who found so many good things to say concerning the first edition of this book. For kind assistance in reading the proofs of this edition my best thanks are due also and are hereby tendered to my wife, and my good friend Gerald Druce, Esq., M.Sc.

H. S. R.

191, Camden Road, London, N.W. 1.
October, 1921.

PREFACE

The number of books in the English language dealing with the interesting subject of Alchemy is not sufficiently great to render an apology necessary for adding thereto. Indeed, at the present time there is an actual need for a further contribution on this subject. The time is gone when it was regarded as perfectly legitimate to point to Alchemy as an instance of the aberrations of the human mind. Recent experimental research has brought about profound modifications in the scientific notions regarding the chemical elements, and, indeed, in the scientific concept of the physical universe itself; and a certain resemblance can be traced between these later views and the theories of bygone Alchemy. The spontaneous change of one “element” into another has been witnessed, and the recent work of Sir William Ramsay suggests the possibility of realising the old alchemistic dream—the transmutation of the “base” metals into gold.

The basic idea permeating all the alchemistic theories appears to have been this: All the metals (and, indeed, all forms of matter) are one in origin, and are produced by an evolutionary process. The Soul of them all is one and the same; it is only the Soul that is permanent; the body or outward form, i.e., the mode of manifestation of the Soul, is transitory, and one form may be transmuted into another. The similarity, indeed it might be said, the identity, between this view and the modern etheric theory of matter is at once apparent.

The old alchemists reached the above conclusion by a theoretical method, and attempted to demonstrate the validity of their theory by means of experiment; in which, it appears, they failed. Modern science, adopting the reverse process, for a time lost hold of the idea of the unity of the physical universe, to gain it once again by the experimental method. It was in the elaboration of this grand fundamental idea that Alchemy failed. If I were asked to contrast Alchemy with the chemical and physical science of the nineteenth century I would say that,