Molecular force

“ It is for the sake of a somewhat commensurate appreciation of vitality, of high-wrought molecular organization, that it is necessary, again and again, to point out the might of potentiality intrinsic to matter, the vast and specific stores of force locked up in the peculiar molecular entanglements which constitute our different substances. ”

“ The properties of substances, though destroyed to sense by combination, are not destroyed in reality. It follows from the persistence of force, that the properties of a compound are resultants of the properties of its components—resultants in which the properties of the components are severally in full action, though mutually obscured. One of the leading properties of each substance is its degree of molecular mobility; and its degree of molecular mobility more or less sensibly affects the molecular mobilities of the various compounds into which it enters. ”

“ It is a matter of demonstration that a theory of molecular forces cannot be constructed on the hypothesis that the forces vary according to some law of the distance from individual material particles, unless the law be such that the force changes sign with the distance so as to become attractive after being repulsive. ”

“ From organic matter, as from all other matter, incident forces call forth that re-action which we know as heat. More or less of molecular vibration necessarily results when, to the forces at work among the molecules of any aggregate, other forces are added. Experiment abundantly demonstrates this in the case of inorganic masses; and it must equally hold in the case of organic masses. In both cases the force which, more markedly than any other, produces this thermal re-action, is that which ends in the union of different substances. ”

“ It is now believed, and to a large extent demonstrated, that the force, apparently lost, has been transformed into heat, electricity, or some other kind of molecular motion, of which the change of shape is only the outward sign. The establishment on a firm foundation of theory and experiment of the so-called conservation of energy, the child of the correlation of physical forces, is one of the first fruits of molecular mechanics. ”

“ Modern science teaches that all physical forces, molar as well as molecular, are mutually convertible. This fact is discussed and illustrated in scientific treatises without number, and its importance is duly appreciated. But there is another fact connected with it, equally well known, the significance of which is not, I think, at all realized: all force in its physical origin is molecular. The power which grinds the wheat in the mill on the stream, or which drives the steam-engines in a factory ”

“ Molecular energies, on the other hand, act with vastly greater force, but at very small distances, and appear sometimes as attractive and sometimes as repulsive forces. Thus solid bodies are held together by a force of cohesion which is very powerful, but acts only at very small distances, as we may see if we break a piece of glass and try to mend it by pressing the broken edges together. We cannot bring them near enough to bring the molecular attraction again into play and make the broken glass solid. ”

“ In an aëriform body the particles are in a state of extreme tenuity, the molecules being themselves, by the influence of some repulsive force, just on the verge where cohesion exerts its decaying power. In fluid bodies the attenuation of the particles is less—the particles and also the molecules are nearer together,—whereas, in the solid body, the forces of cohesion are most strongly exerted, and all the molecular conditions brought more powerfully into action. ”

“ And here we have contemplated, under its several aspects, the correlative general fact that, during these extensive molecular re-arrangements, there are evolved large amounts of energy. In the one case the components of organic matter are regarded as falling from positions of unstable equilibrium to positions of stable equilibrium; and in the other case they are regarded as giving out in their falls certain momenta—momenta that may be manifested as heat, light, electricity, nerve-force, or mechanical motion, according as the conditions determine. ”

“ The molecules of their produced germs must tend ever to conform the motions of their components, and therefore the arrangements of their components, to the molecular forces of the organism as a whole; and if this aggregate of molecular forces be modified in its distribution by a local change of structure, the molecules of the germs must be gradually changed in the motions and arrangements of their components, until they are re-adjusted to the aggregate of molecular forces. ”

“ That the building-up process depends on the action of molecular forces comparable to those by which a growing crystal goes on selecting atom-complexes of its particular kind from the solution around seems highly probable, and this being the case we can understand how under certain circumstances substitutive selections may occur. ”

“ A number of molecules moving in obedience to dynamical laws will pass through a series of configurations which can be, theoretically determined as soon as the structure of each molecule and the initial position and velocity of every part of it are known. The determination of the series of configurations developing out of given initial conditions is not, however, the problem of the kinetic theory: the object of this theory is to explain the general properties of all gases in terms only of their molecular structure. ”

“ While the molecules as wholes increase one another’s oscillations, or derange one another’s oscillations, or both, the components of them cannot be so stably arranged that members of the one group are wholly inoperative on members of the other group. And if they are operative, then there must be a compound form of molecular motion which arises when masses of highly-compounded molecules of unlike kinds, are made to act on one another. ”

“ The molecule of a given substance, though often called an atom, is a system of primitive elements; and elements acting according to the Newtonian law can give rise to molecular systems which, at very small distances, will act according to any other law that may be indicated by molecular phenomena. This other law depends entirely on the number, kind, strength, and geometrical arrangement of the primitive elements which enter into the constitution of the molecule ”

“ The movements of the gaseous molecules are, however, so wonderful that it is hardly surprising that those who are invited to believe these things should demand satisfactory evidence as to the existence of phenomena, which from the nature of the case seem to lie out of the reach of direct inspection by the senses. The methods by which our knowledge of the constitution of matter has been obtained, is by reasoning from the phenomena which our senses reveal to the more refined and supersensible conceptions of molecular physics. ”

“ One of the most remarkable results of the progress of molecular science is the light it has thrown on the nature of irreversible processes—processes, that is, which always tend towards and never away from a certain limiting state. Thus, if two gases be put into the same vessel, they become mixed, and the mixture tends continually to become more uniform. ”

“ All study of man must begin with the study of the atom. Man's life we have seen to be the aggregate of the work of all the cells of his body. But the protoplasm which composes his cells is a chemical compound, and hence subject to all the laws of all the atoms of which it is composed. And its molecules, or the smallest mechanically separable compounds of these atoms, are arranged and related according to the laws of physics, so as to permit or produce the play of certain forces which are always the result of atomic or molecular combination. ”

“ Only, the specific power of the slightly complicated molecule H2O cannot possibly afford any standard for the estimation of the specific power of the immensely more complicated molecule constituting protoplasm. Protoplasm differs from water in proportion to its synthetical wealth. Whatever synthetical wealth may be the symbol of, in its gradations is to be sought the source of all difference in Nature. This is the gist of what chemistry teaches: the work of Nature consists in molecular synthesis. It has required the ceaseless toil of endless ages to build up the molecule of living matter. ”

“ The ordinary mechanical explanation of the molecular states of matter, or states of aggregation, on the basis of the atomic theory, proceeds on the assumption that the molecular states are produced by the conflict of antagonistic central forces—molecular attraction and repulsion—the preponderance of the one or the other of which gives rise to the solid and gaseous forms, while their balance or equilibrium results in the [pg 795] liquid state. ”

“ In molecular bodies motions are correlated in a manner yet unknown, but molecules are known to have interior motions exhibited in response to motions in the ether as its particles impinge on ponderable matter. The correlated structural motions of the molecule may be transmuted by collision with ethereal particles and be converted into heat—a mode of motion—so that which is structural motion will appear as heat, and if the transmutation is carried to a sufficient degree the structure of a molecular body will be destroyed, for by heat molecules are reduced to lower molecules or to atoms. ”

“ As a result of the law of chemical action, that most elementary bodies exist in a condition where two atoms are joined together to form a molecule, it follows, that in most instances the molecular weights of the elements are double their atomic weight. ”

“ We will, then, imagine a molecule magnified to the size of a billiard ball, and the atomic triplet magnified to the size of three marbles, in the triangular position, within that molecule, at its centre; unless acted upon by electricity, when the molecule, the billiard ball, becomes oblate, and the three atoms are ranged in a line within, unless broken up by the mighty force of vibratory action. Nature never gives us a vacuum ”

“ A muscle-curve registers the history of the fundamental molecular change produced by excitation in a living tissue, exactly as the curve of molecular reaction registers an analogous change in an inorganic substance. The two represent the same thing; in the latter the molecular upset is evidenced by the change of conductivity, while in the former it is manifested by the change of form. We have thus means of studying molecular reaction produced by stimulus of varying frequency, intensity and duration. An abyss separates the phenomena of living matter from those of inanimate matter. ”

“ But such conflicts are only those of enlargement, and we anticipate that all chemists look for an enlargement of the molecular horizon precisely in those regions where the forces of cell-life manifest themselves. ”

“ Among the several elements concerned, there are wide differences in molecular mobility, and probably in the rates of molecular vibration. Each is combined with one of the others, but is capable of forming various combinations with the rest. And they are severally in presence of a complex compound into which they all enter, and which is ready to assimilate with itself the new compound molecules they form. Certain of the ethereal waves falling on them when thus arranged, cause a detachment of some of the combined atoms and a union of the rest. ”

“ If we examine carefully all the conditions of matter which we have made the subject of our studies, we cannot but perceive how gradual is the progress of the involved action of the physical forces, as we advance from the molecule—the mere particle of matter—up to the organic combination. At first we detect only the action of cohesion in forming the rude mass; then we have the influence of the crystallogenic powers giving a remarkable regularity to bodies; we next discover the influences of heat and electrical force in determining condition, and of chemical action as controlled by them. ”

“ It should be noted, too, of these bodies, that though they exhibit in the lowest degree that kind of molecular mobility which implies facile vibration of the molecules as wholes, they exhibit in high degrees that kind of molecular mobility resulting in isomerism, which implies permanent changes in the positions of adjacent atoms with respect to each other. ”

“ Those along which there lie most molecules that are easily changed by the diffused molecular motion, and which yet do not take up much molecular motion in assuming their new states. Molecules which are tolerably stable will not readily propagate the agitation; for they will absorb it in the increase of their own oscillations, instead of passing it on. Molecules which are unstable but which, in assuming isomeric forms, absorb motion, will not readily propagate it ”

“ Other things equal, therefore, the molecular mobility of molecules must decrease as their masses increase; and so there must result that progression we have traced, from the high molecular mobility of the uncombined organic elements, to the low molecular mobility of those large-moleculed substances into which they are ultimately compounded. ”