CHAPTER XXIII.
I QUESTION SCIENTIFIC MEN.--ARISTOTLE'S ETHER.
Days and weeks passed. When the opportunity presented, I consulted Dr.W. B. Chapman, the druggist and student of science, regarding the natureof light and earth, who in turn referred me to Prof. Daniel Vaughn. Thislearned man, in reply to my question concerning gravitation, declaredthat there was much that men wished to understand in regard to thismighty force, that might yet be explained, but which may never becomeknown to mortal man.
"The correlation of forces," said he, "was prominently introduced andconsidered by a painstaking scientific writer named Joule, in severalpapers that appeared between 1843 and 1850, and he was followed byothers, who engaged themselves in experimenting and theorizing, and Imay add that Joule was indeed preceded in such thought by Mayer. Thisdepartment of scientific study just now appears of unusual interest toscientists, and your questions embrace problems connected with somephases of its phenomena. We believe that light, heat, and electricityare mutually convertible, in fact, the evidences recently opened up tous show that such must be the case. These agencies or manifestations arenow known to be so related that whenever one disappears others springinto existence. Study the beautiful experiments and remarkableinvestigations of Sir William Thomson in these directions."
"And what of gravitation?" I asked, observing that Prof. Vaughnneglected to include gravitation among his numerous enumerated forces,and recollecting that the force gravitation was more closely connectedwith my visitor's story than perhaps were any of the others, exceptingthe mysterious mid-earth illumination.
"Of that force we are in greater ignorance than of the others," hereplied. "It affects bodies terrestrial and celestial, drawing amaterial substance, or pressing to the earth; also holds, we believe,the earth and all other bodies in position in the heavens, thusmaintaining the equilibrium of the planets. Seemingly gravitation is notderived from, or sustained by, an external force, or supply reservoir,but is an intrinsic entity, a characteristic of matter that decreases inintensity at the rate of the square of the increasing distance, asbodies recede from each other, or from the surface of the earth.However, gravitation neither escapes by radiation from bodies nor needsto be replenished, so far as we know, from without. It may be comparedto an elastic band, but there is no intermediate tangible substance toinfluence bodies that are affected by it, and it remains in undyingtension, unlike all elastic material substances known, neither losingnor acquiring energy as time passes. Unlike cohesion, or chemicalattraction, it exerts its influence upon bodies that are out of contact,and have no material connection, and this necessitates a purely fancifulexplanation concerning the medium that conducts such influences,bringing into existence the illogical, hypothetical, fifth ether, madeconspicuous by Aristotle."
"What of this ether?" I queried.
"It is a necessity in science, but intangible, undemonstrated, unknown,and wholly theoretical. It is accepted as an existing fluid byscientists, because human theory can not conceive of a substance capableof, or explain how a substance can be capable of affecting a separatebody unless there is an intermediate medium to convey force impressions.Hence to material substances Aristotle added (or at least madeconspicuous) a speculative ether that, he assumed, pervades all space,and all material bodies as well, in order to account for the passage ofheat and light to and from the sun, stars, and planets."
"Explain further," I requested.
"To conceive of such an entity we must imagine a material that is moreevanescent than any known gas, even in its most diffused condition. Itmust combine the solidity of the most perfect conductor of heat(exceeding any known body in this respect to an infinite degree), withthe transparency of an absolute vacuum. It must neither create frictionby contact with any substance, nor possess attraction for matter; mustneither possess weight (and yet carry the force that produces weight),nor respond to the influence of any chemical agent, or exhibit itself toany optical instrument. It must be invisible, and yet carry the forcethat produces the sensation of sight. It must be of such a nature thatit can not, according to our philosophy, affect the corpuscles ofearthly substances while permeating them without contact or friction,and yet, as a scientific incongruity, it must act so readily on physicalbodies as to convey to the material eye the sensation of sight, and fromthe sun to creatures on distant planets it must carry the heat force,thus giving rise to the sensation of warmth. Through this medium, yetwithout sensible contact with it, worlds must move, and planetarysystems revolve, cutting and piercing it in every direction, withoutloss of momentum. And yet, as I have said, this ether must be in suchclose contact as to convey to them the essence that warms the universe,lights the universe, and must supply the attractive bonds that hold thestellar worlds in position. A nothing in itself, so far as man's sensesindicate, the ether of space must be denser than iridium, more mobilethan any known liquid, and stronger than the finest steel."
"I can not conceive of such an entity," I replied.
"No; neither can any man, for the theory is irrational, and can not besupported by comparison with laws known to man, but the conception isnevertheless a primary necessity in scientific study. Can man, by anyrational theory, combine a vacuum and a substance, and create a resultthat is neither material nor vacuity, neither something nor nothing, andyet an intensified all; being more attenuated than the most perfect ofknown vacuums, and a conductor better than the densest metal? This we dowhen we attempt to describe the scientists' all-pervading ether ofspace, and to account for its influence on matter. This hypotheticalether is, for want of a better theory of causes, as supreme inphilosophy to-day as the alkahest of the talented old alchemist VanHelmont was in former times, a universal spirit that exists inconception, and yet does not exist in perception, and of which modernscience knows as little as its speculative promulgator, Aristotle, did.We who pride ourselves on our exact science, smile at some ofAristotle's statements in other directions, for science has disprovedthem, and yet necessity forces us to accept this illogical etherspeculation, which is, perhaps, the most unreasonable of all theories.Did not this Greek philosopher also gravely assert that the lion has butone vertebra in his neck; that the breath of man enters the heart; thatthe back of the head is empty, and that man has but eight ribs?"
"Aristotle must have been a careless observer," I said.
"Yes," he answered; "it would seem so, and science, to-day, bases itsteachings concerning the passage of all forces from planet to planet,and sun to sun, on dicta such as I have cited, and no more reasonable inapplied experiment."
"And I have been referred to you as a conscientious scientific teacher,"I said; "why do you speak so facetiously?"
"I am well enough versed in what we call science, to have no fear ofinjuring the cause by telling the truth, and you asked a directquestion. If your questions carry you farther in the direction of forcestudies, accept at once, that, of the intrinsic constitution of forceitself, nothing is known. Heat, light, magnetism, electricity, galvanism(until recently known as imponderable bodies) are now considered asmodifications of force; but, in my opinion, the time will come when theywill be known as disturbances."
"Disturbances of what?"
"I do not know precisely; but of something that lies behind them all,perhaps creates them all, but yet is in essence unknown to men."
"Give me a clearer idea of your meaning."
"It seems impossible," he replied; "I can not find words in which toexpress myself; I do not believe that forces, as we know them(imponderable bodies), are as modern physics defines them. I am temptedto say that, in my opinion, forces are disturbance expressions of asomething with which we are not acquainted, and yet in which we aresubmerged and permeated. Aristotle's ether perhaps. It seems to me,that, behind all material substances, including forces, there is anunknown spirit, which, by certain influences, may be ruffled into theexhibition of an expression, which exhibition of temper we call a force.From this spirit these force expressions (wavelets or disturbances
)arise, and yet they may become again quiescent, and again rest in itsabsorbing unity. The water from the outlet of a calm lake flows over agentle decline in ripples, or quiet undulations, over the rapids inmusical laughings, over a precipice in thunder tones,--always water,each a different phase, however, to become quiet in another lake (asripples in this universe may awaken to our perception, to repose again),and still be water."
He hesitated.
"Go on," I said.
"So I sometimes have dared to dream that gravitation may be thereservoir that conserves the energy for all mundane forces, and thatwhat we call modifications of force are intermediate conditions,ripples, rapids, or cascades, in gravitation."
"Continue," I said, eagerly, as he hesitated.
He shook his head.