state here) to combine with hydrogen in the ratio of one volume to four, so as to yield two volumes of marsh-gas.
It seems to be evident, then, that the typical and primary state of matter is, not the solid, but the gas. And, this being so, it follows that the molecular evolution of matter conforms to the law of all evolution in proceeding from the indeterminate to the determinate, from the simple to the complex, from the gaseous to the solid form. This is no longer a mere presumption; if the nebular hypothesis, so called, after being stripped of its non-essential features, is recognized as a true theory—as it is by all the prominent physicists of the day since the recent revelations of the spectroscope—the gaseous form of matter, in fact, precedes the liquid and solid forms in the order of Nature, and the solid is not the initial, but the concluding term of material evolution. Inasmuch, therefore, as the explanation of any phenomenon consists in the exhibition of its genesis from its simplest beginnings, or from its earliest forms, the gaseous form of matter is the true basis for the explanation of the solid form, and not conversely the solid for the explanation of the gas.
From the foregoing considerations I take it to be evident that the true relation between the molecular states of matter is the exact reverse of that universally assumed. The universality of this assumption, however, indicates that it is not due to a mere chance error of speculation, but to some natural bias of the mind. The question arises, therefore: What is the origin of this prevalent delusion respecting the constitution of matter? I believe the answer to this question to be exceedingly simple, and important in proportion to its simplicity. There are certain fallacies to which the human intellect is liable by reason of the laws of its growth which I propose to call structural fallacies, one of which is that the intellect tends to confound the order of the genesis of its ideas respecting material objects with the order of the genesis of these objects themselves. It is well known that the progress of our knowledge depends upon analogy—upon a reduction of the Strange and Unknown to the terms of the Familiar and Known. In a certain sense it is true, what has been often said, that all cognition is recognition. "Man constantly institutes comparisons," says Pott ("Etymologische Forschungen," ii., 139), "between the new which presents itself to him, and the old which he already knows." That this is so is shown by the development of language. The great agent in the evolution of language is metaphor—the transference of a word from its ordinary and received meaning to an analogous one. This transference of the name descriptive of a known and familiar thing to the designation of an unknown and unfamiliar thing typifies the proceeding of the intellect in all cases where it deals with new and strange phenomena. It assimilates these phenomena to those which are known; it identifies the Strange, as far as possible, with the Familiar; it apprehends that which is extraordinary