Structure of Matter.

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yield no new or strange elements, the probabilities are in favour of the compound nature of many "elements" of the chemist.

If with Newton we speak of dense invisible units, those are only symbolic, yet still they seem verified in chemical experiments which manifest particles of specific weight, size, elasticity, affinity, differences of quality, with chronometric vibrations-not force, but conditions of force. Get rid of the atom, as Boscovich does, substitute mere geometrical points, points without dimensions, as centres of force, force loci, which attract and repel each other in such wise as to be kept apart and at specific distances; behaving, so far as external bodies are concerned, just as an atom would. Pass on with Sir William Thomson and Helmholtz, to the vortex-atom theory, that matter consists of rotating portions of a something which fills the whole of space, that is, vortex-motion of an everywhere present fluid. Add to this, every so-called atom of any one substance, wheresoever we find it, on the earth, in the sun, or coming to us from cosmical spaces, possesses precisely the same physical properties, measurable dimensions, with shape, motion, laws of action, which we subject to scientific investigation. Then take a drop of water, and by means of a galvanic battery decompose it into the constituent gases; this shows that the parts may be separated until they are so small, that if again divided, the halves or parts are no longer similar to one another; but one is oxygen, the other hydrogen. Thus we have arrived at the grained structure of the whole. We are not wholly without hope that we may some day know the real weight of every atom-not merely the relative weight of several atoms; but the number in the given volume of any material; that the form and motion of the parts of every atom, and the distances by which they are separated, may be calculated; that the motions by which heat, electricity, light, are produced, may be shown by exact mathematical diagrams; that the fundamental properties of the intermediate and possibly constituent medium may be discovered. We shall then, for a while, turn from the motion of planets and music of spheres, to take our fill of wonder as to the mystic maze in which those tiny atoms run.

How finely grained water is, may be seen from the fact that were it possible to draw out a film 100,000,000th of an inch in thickness, it would probably still contain a few particles of water in its thickness.1 As to the ultimate particles of the elements, by a rough process, Cauchy obtained the 400,000,000th part of an inch as their diameter. By a calculation upon what is called the electricity of contact of different metals, it is thought to have been ascertained that the grained structure must exceed the 700,000,000th part of an inch. By the molecular motion of gases, a result has been obtained which indicates that the 500,000,000th part of an inch may be the size of the particles. These points or atoms manifest powers of attraction and repulsion; march under three banners as gases, fluids, solids; but it is probable that every one is capable of existing in all three forms. The mysterious complexity of their nature may be inferred from gases. The result arrived at by several inquirers as to the molecular motion of gases is, that the average distance between the several particles of a gas at the ordinary temperature and pressure of the air, must be something between the 6,000,000th part of an inch and the 10,000,000th part of an inch." The number of particles in a cubic inch of air is, approximately, about the number 3 with twenty cyphers after it; and as a plum is to the whole earth, so is a particle of water to the whole drop; there being in that drop about 10", that is, 100,000,000,000,000,000,000,000,000. The particles of a gas are known to be free, detached from one another, and constantly flying about in all directions. The velocity of particles of hydrogen, according to Foulis' experiments, must be about 6055 feet per second at o° C. This is a higher velocity than has ever been attained by a cannon ball. Joule's estimate for hydrogen was 6225 feet the second at temperature 60° F., and 6055 the second at freezing point. Clerk Maxwell and Boltzman have ascertained that in a mass of hydrogen, at ordinary temperature and pressure, every particle, on an average, has 17,700,000,000 collisions per second with other particles; that is to say, in every second its course is changed 1 "Recent Advances in Physical Science," p. 311: P. G. Tait, M.A. 2 Ibid. p. 315.

Movements of the Particles.

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17,700,000,000 times; and, yet, the particles are moving at the rate of 70 miles the minute. When rude voices say "The Lord never passeth by; not in the wind, not in the earthquake, not in the still, small voice;" we cannot but marvel that some cunning creatures are so savage as not to perceive God unless He thunders on them.

The idea of the gaseous state in which a given space contains millions and millions of molecules in rapid movement in all directions, each having millions of encounters in a second, is not of universal application. It relates to the peculiar physical conditions of our planet, and doubtlessly to the neighbourhood of the bodies of the solar system; but what is the condition of the molecules in those regions of space remote from the influence of gravitation, where rarefaction is at its utmost, the minutest particles of matter are scarce and rarely meet a fellow with which to collide? Crookes shows, in the highly rarefied vessels under his superb manipulation, that the free path of the molecules is made so long as their collisions are rare; and they cease as a whole to have gaseous properties, and become invested with hitherto masked properties. In this outside world, to use the words of the distinguished physicist, “a world where matter exists in a fourth state," these molecules move and obtain available kinetic energy, there the corpuscular theory of light holds good, there light does not always move in a straight line, there the impacts of imponderable molecules produce intense heat.1

If we look at Nature in her working dress, we find that the elements are not apparently of the same relative use and importance. It is a startling fact that the variety of existences which Nature contains, far from exhausting all the forms and combinations of which the elements are capable, only uses a few. The solid globe, whithersoever our search extends, is composed of say-silicon, aluminium, iron, magnesium, sodium, potassium, and oxygen. The broad ocean composes its vast masses of fluid principally from two elements-oxygen and hydrogen, and the salt consists mainly of chlorine and sodium. The air is formed of nitrogen and oxygen. The

1 W. Crookes, F. R. S., "On the Illumination of Lines of Molecular Pressure, and the Trajectory of Molecules." Proceedings, Royal Society, vol. xxviii. no. 191.

animal and vegetable worlds, innumerable in forms and functions of life, are chiefly built of carbon, nitrogen, hydrogen, oxygen. It is, indeed, astonishing that the great variety exhibited in the whole world is unfolded out of few materials. The Creator has taken but a handful of elements wherewith to form, in the main, the gorgeous structure of our dwelling. Do we ask why? The answer comes-as yet the world, to us at least, is rudimentary. Eternity and space contain endless surprises and possibilities; we know not what we shall be. There are latent forces of development which, when called forth, will exhibit new and exquisite powers. The elements, now little used, may hereafter display magnificent variety and surpassing beauty. The great Master has wrought charming music with few notes; what soul-stirring melodies will awake gladness when all the chords are touched!

Listen to the life-throb of our universe. By scientific use of imagination, we may conceive all the mechanical, chemical, vital operations of the world, as resulting from an infinite congeries of invisible atoms or mathematical points of attraction and repulsion. These countless centres are so many starting points of motion, causing atoms to cluster into molecules, and molecules into masses. In other words: "Atoms and molecules are little magnets with mutually attractive and mutually repellent poles. The attracting poles unite, the repelling poles retreat; vegetable, as well as mineral forms, are the final expression of this complicated molecular action."1 This life-throb of the whole visible and palpable world is a pulsation going forth every instant from the Eternal Energy, bringing out from the invisible and intangible that which is visible and tangible.

To develop the visible from the invisible, there must be a passage from the one to the other, or an ethereal medium, a stage in which the energy had passed from one and had not arrived at the other: that passage or medium none of us can explain. Further, if we assume that all energies are reducible to One Energy, and that all forms of matter are derived from one primeval substance, is not this an attempt to explain the creation of matter? for it is demonstrably impossible for

"Matter and Force: " Prof. Tyndall.

The Vastness of Continual Change.

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variety to have unfolded itself from this supposed primitive physical unity. The change must have come from without, and even allowing that the change can be mechanically formulated, we recognise in it the Unknown Energy. The variety called Nature did not evolve itself from unity, neither does Nature of itself, apart from the primal Energy, guide or maintain the variety of continual change. Organic force does not seem to be interchangeable with mechanical. No physical force, that we know of, can be converted into that which is called vital, or counted as the correlative of mental change. Again and again there have been intrusions of new things, interpenetrations and modifications of energy. If chemical action differs from mechanical; if life is not chemistry, and certainly it is unknown in our laboratories; and if mind is not matter; certainly many and great are the changes that have been wrought in the nature and essence of things.

View the whole from another standpoint, from the brow of a hill when all is still, the breeze having died away. The air is clear, and we listen in vain to catch a sound other than the low murmur of waves breaking on the shore. The shepherd's flock slumbers beneath the elm-tree shadows, and cattle stand in cool hollows by the river-side. The green meadows, fresh and luxuriant, seem also asleep, Nature is in repose. Is it indeed so? Come again, after a little time, and a change has been wrought. Even the flowers which bedeck the soil, the very substance of those hills standing firm, the deep sea so placid, the quiet, still air, are all in motion. From year to year the limestone of the rock changes its hard lineaments. The elastic sod, pressed by our feet, is not the same, its materials are being altered, carried away, renewed. Changeable the wind, so the sea. All things are working, and for ever in vast complications, every one child and parent of other. The contemplative mind beholds every day the passage of things invisible into sight, the transfer of the seen into the unseen. The passing away of the world might be called a pause, and the annihilation of solid spheres a rest, rather than the crash of destruction. We reverently lay all our science at the feet of the Eternal.

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