NOTHING is so fascinating in science as an ingenious, but unproved, theory. Once proved to the dignity of a “law,” it becomes a thing to be learnt, and exchanges the charm of an uncertain denouement for the cold severity of a lesson. The strange revelations of modern chemistry in relation to the nature of the so-called elements have kindled among all scientific student!'! an intensely eager anticipation of the discovery of some simple scheme into which all the accumulated facts shall drop in natural connection, of the thread which links the myriad observations of patient explorers into a perfect chain. “We cannot but feel,” said Mr. Crookes at the Royal Institution recently, 'oj that unless some approach to an answer to these questions can be found, our chemist-rv. after nil, is something profoundly unsatisfactory.elements perplex us in our researches, baffie us in our speculations, and haunt us in our very dreams. They stretch like an unknown sea before us, mocking, mystifying, and murmuring strange revelations and possibilities.” Mr. Crookes detailed his speculations on the genesis of the elements at the last meeting of the British Association, and we then reported his address in full. He has lately presented his ideas again in rather more popular language to the fashionable world of science assembled in Albemarle Street, and many of the keenest minds in England are pondering his theory. A few weeks since, Sir William Thomson narrated to a similar audience his idea of the way in which the sun was formed some twenty millions of years since, by the rushing together of atoms in such quantity and with such force as to provide a source of heat for this solar system up to the present date and about ten million years longer. Mr. Crookes takes us back a [few steps farther. What was the condition before the atoms had themselves come into shape, if, indeed, they are not eternal, when creation was, in the expressive language of Scripture, “without form and void”? Mr. Crookes assumes a condition which he designates “protyle,” the “proteule” of Aristotle, the formless stuff of the Book of Wisdom, the materia prima, the unknown and unknowable origin of matter, the “fire mist,” as Mr. Crookes himself happily, but vaguely, terms it. Now suppose in the midst of this protyle the introduction of external energy in some form or other, and an internal action corresponding to cooling. The energy has period* of swell and ebb, and it forces the protyle to itself and to develop first the lightest of atoms, say hydrogen. These atoms would then be themselves stores of energy, kinetic from their internal motions, and potential from their tendency to coalesce with other atoms by gravitation or chemically. Each new formation would tend to the formation of others by refrigerating the surrounding protyle, and we should get sets of atoms of regular progressive weight. Now (without following Mr. Crookes in all the steps of his argument) see how these elements group themselves, and notice the regular ebb and flow of the formation. It is not necessary to continue the diagram, which is a modification of one first drawn by Professor Emerson Reynolds. It will be found complete in this journal for' September 25, 1886. What is to be noticed is this: When energy first acted on protyle, its first accomplishment was the formation of the hydrogen atom. A few thousands of years later it had got as far as lithium; next came beryllium, boron, and carbon. So far, positive elements only had been created in regular progression of atomic weight and of valency. Now the pendulum returns, the ebb set!'! in, negative elements are formed until the center is reached, when a new impetus is given, and new creations result in similar order. As the pendulum reaches a corresponding stage in each swell or ebb, elements of curiously corresponding characteristics result. So we have chlorine, bromine, and iodine; calcium, strontium, and barium; arsenium, antimonium, and bismuth found at corresponding points of the pendulum's swing. A great deal of this theory is due to the labors of other chemists—Newlands, Mills, and Mendelejef especially; but Mr. Crookes has, no doubt, most. ingeniously fitted all their observations into his comprehensive scheme. His own special contribution to his theory, however, is very striking. He has worked for many years on yttrium and its spectra. By the most delicate of tests he has shown that yttrium can be differentiated or fractionated into several varieties, all showing the true yttrium spectrum, but each with some marked differences of its own in the subordinate lines. This observation is what led Mr. Crookes to imagine that the creation of yttrium was itself a work of time, of slow evolution, leaving its effects in trifling variations of the weight of the atoms, which altogether go to make up yttrium. If that be so, is it not possible too that the whole genesis of the elements is a very slow process of evolution? The occurrence of sneii groups as manganese, iron, nickel, and cobalt, with their curiously similar chemical properties, all created apparently at close intervals, goes to support this idea. Much more will certainly be heard of this theory. We make no pretension of criticising it. Our design has been only to present its salient features in outline, leaving students who may wish to understand it more fully to refer to the emiment author's own words.— Ch.emist and Druggist.