Post 00311
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In those ever-moving and indivisible atoms he touches the very corner-stone of the modern scientific conception of matter. It is hardly an exaggeration to say that in this conception we are brought into contact with a kind of transcendental physics. A new world for the imagination is open–a world where the laws and necessities of ponderable bodies do not apply. The world of gross matter disappears, and in its place we see matter dematerialized, and escaping from the bondage of the world of tangible bodies; we see a world where friction is abolished, where perpetual motion is no longer impossible; where two bodies may occupy the same space at the same time; where collisions and disruptions take place without loss of energy; where subtraction often means more–as when the poison of a substance is rendered more virulent by the removal of one or more atoms of one of the elements; and where addition often means less–as when three parts of the gases of oxygen and hydrogen unite and form only two parts of watery vapor; where mass and form, centre and circumference, size and structure, exist without any of the qualities ordinarily associated with these things through our experience in a three-dimension world. We see, or contemplate, bodies which are indivisible; if we divide them, their nature changes; if we divide a molecule of water, we get atoms of hydrogen and oxygen gas; if we divide a molecule of salt, we get atoms of chlorine gas and atoms of the metal sodium, which means that we have reached a point where matter is no longer divisible in a mechanical sense, but only in a chemical sense; which again means that great and small, place and time, inside and outside, dimensions and spatial relations, have lost their ordinary meanings. Two bodies get inside of each other. To the physicist, heat and motion are one; light is only a mechanical vibration in the ether; sound is only a vibration in the air, which the ear interprets as sound. The world is as still as death till the living ear comes to receive the vibrations in the air; motion, or the energy which it implies, is the life of the universe.
Physics proves to us the impossibility of perpetual motion among visible, tangible bodies, at the same time that it reveals to us a world where perpetual motion is the rule–the world of molecules and atoms. In the world of gross matter, or of ponderable bodies, perpetual motion is impossible because here it takes energy, or its equivalent, to beget energy. Friction very soon turns the kinetic energy of motion into the potential energy of heat, which quickly disappears in that great sea of energy, the low uniform temperature of the earth. But when we reach the interior world of matter, the world of molecules, atoms, and electrons, we have reached a world where perpetual motion is the rule; we have reached the fountain-head of energy, and the motion of one body is not at the expense of the motion of some other body, but is a part of the spontaneous struggling and jostling and vibration that go on forever in all the matter of the universe. What is called the Brunonian movement (first discovered by the botanist Robert Brown in 1827) is within reach of the eye armed with a high-power microscope. Look into any liquid that holds in suspension very small particles of solid matter, such as dust particles in the air, or the granules of ordinary water-color paints dissolved in water: not a single one of the particles is at rest; they are all mysteriously agitated; they jump hither and thither; it is a wild chaotic whirl and dance of minute particles. Brown at first thought they were alive, but they were only non-living particles dancing to the same tune which probably sets suns and systems whirling in the heavens. Ramsay says that tobacco smoke confined in the small flat chamber formed in the slide of a microscope, shows this movement, in appearance like the flight of minute butterflies. The Brunonian movement is now believed to be due to the bombardment of the particles by the molecules of the liquid or gas in which they are suspended. The smaller the particles, the livelier they are. These particles themselves are made up of a vast number of molecules, among which the same movement or agitation, much more intense, is supposed to be taking place; the atoms which compose the molecules are dancing and frisking about like gnats in the air, and the electrons inside the atoms are still more rapidly changing places.
We meet with the same staggering figures in the science of the infinitely little that we do in the science of the infinitely vast. Thus the physicist deals with a quantity of matter a million million times smaller than can be detected in the most delicate chemical balance. Molecules inconceivably small rush about in molecular space inconceivably small. Ramsay calculates how many collisions the molecules of gas make with other molecules every second, which is four and one half quintillions. This staggers the mind like the tremendous revelations of astronomy. Mathematics has no trouble to compute the figures, but our slow, clumsy minds feel helpless before them. In every drop of water we drink, and in every mouthful of air we breathe, there is a movement and collision of particles so rapid in every second of time that it can only be expressed by four with eighteen naughts. If the movement of these particles were attended by friction, or if the energy of their impact were translated into heat, what hot mouthfuls we should have! But the heat, as well as the particles, is infinitesimal, and is not perceptible.