42 



♦ KNOAVLEDGE ♦ 



[Dec. 1, 1885. 



The elements seldom occur in the free state, nearly all 

 bodies being compound, or formed by the union of two 

 or more — rarely exceeding four — elements. Oxygen, 

 ■which is the most abuudnnt and important of all, and, 

 when uncombined, a tasteless and invisible gas, enters 

 into nearly one-half of the crust of the globe ; while of 

 such limited variety of stuif is the infinite complexity 

 of things in earth and heaven produced, that the mass of 

 matter in the universe, as the spectroscopic analj'sis of 

 light radi;ited from the heavenly bodies shows, is made 

 up of aboTit fourteen elements. 



Our knowledge of molecules, still more of atoms, is yet 

 in its infancy, and it would seem that particles which 

 are beyond the range of our most powerful microscopes 

 to reveal may be as astoundingly complex as the giant 

 orbs of the heavens — nay, as the universe itself. Many 

 ingenious experiments and calculr.tions have been made 

 to arrive at their size and structure, but they leave the 

 problem of the ultimate divisibility or indivisibility of 

 matter where they found it. The seven-hundredth 

 millionth part of an inch is considerably under the 

 thickness to which, if it could be done, a plr.te of zinc or 

 of copper could be reduced without making it cease to be 

 zinc or copper as we know and handle them. The ovum 

 of mammals, which averages about the hundred-and- 

 fiftieth of an inch in diameter, prob.^bly contains not 

 less thnn five thousand billions of molecules. But, as 

 showing how approximate only such estimates are, we 

 are, in using the highest optical aid we can command, 

 about as far from a knowledge of the ultimate 

 structure of organic bodies as we should be of 

 the contents of a newspaper seen with the naked eye 

 one-third of a mile off. The only hint of a possible limit 

 having been reached in the elements is in the invariable- 

 ness of the weights in which they combine with each 

 other. Each atom has its own fixed weight ; and unites 

 in never-varying proportions with other atoms to form 

 molecules whose properties are unlike those possessed by 

 the uncombined atoms ; e.g., oxj-gen in its simjile state 

 is the source of combustion, but united with hydrogen it 

 forms water, which extingiiishes combustion. Whether 

 we take water in large or small quantities, from the 

 clouds, or from the ocean, or from the fluids of living 

 things, and decompose or break up its molecules, they 

 will always be found to contain 16 parts by weight of 

 oxygen to 2 parts by weight of hydrogen ; whether we 

 take salt from the sea or from the blood of animals, its 

 molecules always consist of fixed proportions of chlorine 

 and sodium, 35i- parts of the one and 23 of the other ; 

 in each and every case any excess of either element 

 remains uncombined — left out in the cold for want of a 

 partner. 



We have now arrived at a point when the grounds for 

 the assumptions alre:idy made — and there are others to 

 follow, — concerning the natureof matter throughout space, 

 whether in masses large or small, in molecules, atoms, 

 and the tL^nuous ether must ba stated, lest confusion arise 

 in the mind. 



If atoms are unchangeable in their properties, and 

 changeable only in their relitious through combination 

 with other atoms, and in their distribution in space, it 

 follows that all changes are due to motion. 



Motion throughout the universe is produced or de- 

 stroyed, quickened or retarded, increased or lessened, by 

 two indestructible Powers of opposite nature to each 

 other — Force and Energy. Each of these is a con- 

 venient term for unknown . ultimate causes of cer- 

 tain phenomena of motion and relations between mo- 

 tions, but there are fundamental differences between 



them which require explanation to prevent confusion in 

 thought.* 



II. Force is that which produces or q^iickens motions 

 binding together two or more particles of matter having 

 weight, and which retards or resists motions tending to 

 separate such particles. 



When this force acts between visible masses of matter, 

 large or small, distant or near, it is called Gravitation ; 

 when it acts between the invisible molecules composing 

 masses, it is called molecular attraction, or Cohesion ; 

 when it acts between the elementary substances or atoms 

 uniting them chemically into molecules, it is called 

 chemical attraction, or Affinitij. 



As this Force inheres in, and can never be taken from, 

 ponderable matter, every atom possesses the tendency to 

 attract, and — in the absence of any opposing Energy 

 sufficient to overcome such tendency — the power to 

 attract every other atom, as well as to resist any sepa- 

 rating power or counteracting Energy. The sum total of 

 this Force is constant, and its several qualities are grouped 

 u.nder one doctrine, called the Persistence of Force. 



III. Enerf/ij is that which produces or quickens motions 

 separating, and which resists or retards motions binding 

 together, two or more particles of matter or of tlic 

 ethereal medium. The importance of these words in 

 italics will appear later on. 



The sum total of Energy in the universe is a fixed 

 quantity, but it is not, like Force, bound up with matter 

 so that it cannot be transferred. It exists whether it 

 acts or not, and therefore can be stored up. 



Energy is of two kinds, active f.nd passive, or, in the 

 terms of science, kinetic and potential. E.g., dealing 

 with masses only, potential energy is seen in a stone 

 lying on a roof or on a mountain, in a clock wound up 

 but not going, in a bed of -coal, in gunjiowder. Kinetic 

 energy is seen in the stone fr.lling, the clock going, the 

 cor.l burning, the powder exploding. Not only does the 

 potential pass into the kinetic and vice versd, but the 

 several forms of kinetic energy pr,S3 into one another 

 — motion into heat, he;-,t into electricity, electricity into 

 heat and light and chemical action, a definite amount of 

 any one form of energy passing into an equivalent 

 amount of the other, the one disappearing as the other 

 appears. And the tendency of .all passive energy is to 

 be converted into active energy until a dead or uniform 

 level is reached, as in bodies of the same temperature 

 wherein no differences of sepn,raling power remain. The 

 significance of this will be more apparent when the ulti- 

 mate destiny of the universe is considered. 



The qualiti.'S of convertibity and indestructibilitj' are 

 grouped under one doctrine, called the Conservation of 

 Energy. 



The Persistence of Force and the Conservation of 

 Energy may be grouped together under the doctrine of 

 the Indestructibility of Power. 



Force is the attracting power ; Energy is the repelling 

 power; and by the antagonism of these the work of the 

 universe is performed. Every mass pulls every other 

 mass by the force of gravitation — the earth the moon, 

 the sun the earth, .some other star the sun, and vice 



* If the readers of Knowlkdse find their conception of cosmic 

 relations made clearer by this paper, their thanks are due to Mr. 

 Grant Allen, not to me. His interest in this effort of mine has taken 

 the generous form of lending me his unpublished notes on this 

 subject, and these are so important and satisfactory a contribution 

 to tlieories of the dynamics of the universe that it is to be hoped 

 Mr. Allen will speedily give us a book that I venture to think 

 will correct and supplement the current manuals, none of which are 

 altogether free from confusion in statements of the relations 

 between Force and Energy. 



