Matthew Moncrieff Pattison Muir

“ The product of the union of oxygen and sulphur, i. e., of oxygen with an electro-negative body, belongs to the class of acid oxides; the product of the union of oxygen and silver, i. e., of oxygen with an electro-positive element, belongs to the class of basic oxides.
If this view of the composition of oxides were granted—and a most ingenious and plausible theory it was—why should we not proceed a step further and say that an acid acts so readily upon a base, because, in the first, negative electricity predominates, while the prevailing electricity in the latter compound is positive? ”

“ A residual phenomenon is, then, a phenomenon which is not fully explained by any established theory; but at the same time it is not a phenomenon which is absolutely contradictory to any such theory, for, if this were the case, the theory in question must perforce be abandoned.
Advances are made in natural science by a judicious use of hypotheses. Facts are accurately observed, or are gained by exact experiment, and are compared with facts; inferences are drawn, and are compared with other inferences, until a good working hypothesis is attained. ”

“ The chemical elements have long been regarded as truly elementary bodies, that is, as bodies from which no form of matter other than themselves can be obtained. But phenomena presented by the spectra of certain of these elements seem almost inexplicable by the commonly accepted view. Mr. Lockyer has carefully examined many of the so called elementary spectra, at temperatures varying from that of a gas flame to that of the star Sirius, and, in order to explain the phenomena noticed, he has provisionally adopted the hypothesis that the so-called elements are really compound bodies. ”

“ The observed residual phenomena of nature which yet await solution are many and varied; every branch of scientific work presents its own list. Let me glance at a few, and they shall be chiefly chosen from those phenomena which are investigated by the science of chemistry.
That the molecules of the elements, i. e., the smallest individual parts which exhibit the properties of the elements, consist of yet smaller parts, or atoms, is undoubted. The generalization holds, with few exceptions, that the elementary molecules contain each two atoms. ”

“ We can define energy: the phlogisteans could not define phlogiston. But in the ethereal philosophy of the future will it not be said of the present workers in science that they could not define ether, but even spoke of it at times as "not gross nor ponderable matter"? ”

“ The new school averred that "compound radicle" was an expression generalizing a class of facts; that the reactions of bodies were most simply explained by supposing that when acted on by chemical force the little parts of these bodies behaved as having a definite structure; and that therefore the formula of a given body might be written as containing different compound radicles under different conditions.
The fault of the old chemistry was that more attention was paid to symmetrical formulæ than to reactions; the merit of the new consisted in bringing the student once more back to nature. ”

“ The older workers could not define phlogiston; we are able to define energy, and therefore we can see clearly where they saw but darkly. Chemistry now acknowledges that the properties of a compound are not only determined by the composition of the matter of that compound, but by the amount of energy associated with that collocation of matter. ”

“ Once more, the examination of residual phenomena may be, and has often been, of immense service to science, in freeing naturalists from the tyranny of an established theory which has for long been regarded as of necessity affording a full explanation of the entire series of facts to which it is applied.
The tyranny of orthodoxy is not unknown in science. ”

“ The earlier study of biological science tended to show a great simplicity in the vital processes occurring among all living things; but the more advanced study of the same science has altogether overthrown the simplicity of the earlier scheme. Certain animals, and classes of animals, seem deliberately to adopt strange expedients for reproducing their kind, as if to warn us against such hasty generalizations. ”

“ When it became necessary once more to adopt the idea of compound radicles, the theory of substitution was found to be strengthened, not weakened, thereby. Many reactions were made clear by supposing that an element might be substituted by a group of elementary atoms, by a compound radicle. But in adopting the idea of compound radicles the substitutionist yet maintained that the chemical compound was a distinct whole, made up of parts he admitted, but, nevertheless, having these parts so modified and merged in one another that the resultant acted as an homogeneous compound. ”

“ We appear to be now fairly embarked in the prosecution of molecular dissection, and our chief guide is the theory of valency, itself a development of the dualistic chemistry.
Each elementary atom, I have said, seems to have the power of directly binding to itself a maximum number of other atoms; but it would further appear as if the groups of atoms thus produced had also a certain binding power, but this more indefinite than the atomic binding power, and very variable under different physical conditions. ”

“ The two parts of a compound were respectively endowed with positive and negative electricity. When two bodies combined, the positive electricity in one neutralized the negative electricity in the other; hence the phenomena of light and heat noticed in chemical combination. An element might contain an absolutely greater quantity of positive electricity than another and nevertheless belong to the electro-negative series of elements: thus sulphur and oxygen readily combine to form a substance which, when dissolved in water, yields an acid. ”

“ From this hypothesis deductions are made which must necessarily prove true if the hypothesis be correct; the truth or falsity of the alleged facts is tested by an appeal to Nature; and so wider hypotheses are gained, each in turn being tested and tried by an appeal to facts, until, finally, that generalization is reached which includes in its expression so many and so varied phenomena that to it is given the name of a "law of Nature." ”

“ How should we have imagined the possibility of fertilization for successive generations, of hermaphroditism, or of reproduction by fissure, etc., being found among the methods which Nature adopts for replenishing the earth, had we contented ourselves with an examination of the comparatively simple methods of ordinary sexual reproduction? ”

“ And, moreover, chemistry aided by physics has concluded that the properties of a body "are dependent on the variations of the energy of the body, and not on its total value," and therefore that "it is unnecessary, even if it were possible, to form any estimate of the energy of the body in its standard state." ”

“ Newton's theory of comets, viz., that these bodies obey the law of gravitation while revolving in oblique orbits round the sun, appeared to account for the facts which had been noticed concerning the comet of Halley; but the period calculated for Encke's comet, on this hypothesis, was found to be rather longer than the actual, observed period, and, moreover, the duration of the observed period showed a small but regular diminution. Hence, Newton's theory, taken alone, was not sufficient to account for the facts. ”

“ We have learned to extend the meaning of the word thing—we speak of "the power of doing work" as a measurable and definite thing—although not as matter: and we know that when a body burns it loses a certain amount of this power of doing work, or, as it is more shortly put, of energy. ”

“ But, lastly, the study of residual phenomena may aid in freeing our minds from that fascinating, but surely erroneous, idea which a mere superficial acquaintance with natural science tends so much to strengthen, viz., that Nature is, and indeed must be, extremely simple. ”

“ Hence, given the number of atoms in a molecule, and the valency of each atom, it became possible to calculate the number of different arrangements of these atoms which could be produced; and careful experiment has often succeeded in preparing all the different, theoretically possible, compounds. The difference of properties of such compounds, i. e., of compounds the molecules of which are constituted of the same number of the same atoms, but differently arranged, is attempted to be indicated in the "structural" or "rational" formulæ of modern chemistry. ”

“ If sodium be thrown on to water, caustic soda is produced, a substance made up of hydrogen, oxygen, and the simple radicle sodium; by another reaction a substance can be obtained consisting of hydrogen, oxygen, and the compound radicle nitryl (NO2) . These two bodies have analogous formulæ, Na OH and (NO2) OH, they may both be regarded as derived from water, H HO, by the replacement of one half of the hydrogen by a radicle; in one case by Na, in the other by NO2. Again, the whole of the hydrogen in water may be replaced by sodium, with production of the compound sodium oxide, Na2O. ”

“ Here was a residual phenomenon—a phenomenon not absolutely contradictory of the law, that that group of bodies called acids is characterized by the presence of oxygen, but certainly a phenomenon demanding accurate investigation. ”

“ Mankind has until lately been content with space of three dimensions, but the bolder and more dashing spirits among the mathematicians have dared to look forward to a better world than this where they may revel in space of four dimensions. ”

“ Darwin and others have established the generalization that members of more than one species of plants derive their nourishment mainly from animal matter, and that these plants thrive better upon such food than upon the ordinary kinds of plant-food. ”

“ Many animal instincts, e. g., the curious instinct which prompts the cuckoo to lay a single egg in a nest not her own, connected as this instinct undoubtedly is with the similar but less perfectly developed instinct of the American Molothrus bonariensis, have not as yet been completely brought within the sphere of any wide generalization. ”

“ But oxygen and sulphur are both electro-negative elements. Berzelius supposed that sulphur contained a large quantity of both electricities, the negative predominating. When this element combined with oxygen, the positive electricity of the sulphur was Supposed to be neutralized by the negative electricity of the oxygen, so that the negative electricity of the sulphur was concentrated or rendered more apparent. ”

“ But this phenomenon, apparently inexplicable in terms of any known law, upon exact investigation finds demonstrable explanation without recourse being had to the action of an unknown agent. The experiment is carried out by pouring liquid sulphur dioxide—a liquid which boils at a temperature lower than that of the freezing point of water—into a red-hot platinum crucible, immediately adding a little water, and quickly turning out the ice which is produced. ”

“ Experiment shows that when a liquid is suddenly brought into contact with a highly heated smooth surface, vapor is evolved which surrounds the mass of liquid as it were with a screen through which the heat, radiated from the hot surface underneath, passes but slowly ”