CHAPTER XI Conservation of Energy--A Discussion of the Relation of the Doctrine of Conservation of Energy, and the Possibility of Perpetual Motion

Conservation of Energy is a doctrine to the effect that energy, like matter, is indestructible, and, except by the infinite, can neither be created nor destroyed; that the sum total of all Energy in the world remains constant; that it may manifest itself in different forms, as heat, magnetism, electricity, mechanical motion, vaporization, but that the sum total remains the same.

Nothing could be more satisfactorily proved than this doctrine, and, yet, like Newton's theory of universal gravitation the proof does not amount to a mathematical demonstration. Mathematics demonstrates the conformity of the doctrine of universal gravitation, and of Conservation of Energy with all known natural processes and observed phenomena; but mathematics does not otherwise prove the Universality of Gravitation nor Conservation of Energy.

Writing on this subject of proof, with reference to gravitation, the late and eminent Simon Newcomb says:

"It may be inquired, is the induction which supposes gravitation universal so complete as to be entirely beyond doubt? We reply that within the solar system it certainly is. The laws of motion as established by observation and experiment at the surface of the earth must be considered as mathematically certain. Now, it is an observed fact that the planets in their motion deviate from straight lines in a certain way. By the first law of motion, such deviation can be produced only by a force; and the direction and intensity of this force admit of being calculated once that the motion is determined. When thus calculated, it is found to be exactly represented by one great force constantly directed toward the sun, and smaller subsidiary forces directed toward the several planets. Therefore, no fact in nature is more firmly established than is that of universal gravitation, as laid down by Newton, at least within the solar system."

It will thus be observed that the theory of Universal Gravitation is not by scientific men claimed to have been mathematically demonstrated, but its proof is regarded as resting upon its conformity with known natural phenomena. The same thing is true of Conservation of Energy. Scientists and mathematicians do not claim proof of this doctrine other than by its universal coincidence with all natural manifestations, and, yet its proof rests upon such a solid structure of coincidence and conformity with all known things in nature, that now all scientific research begins with its assumption, and with the exclusion of the possibility of Perpetual Motion.

It is not within the purview of this work to give a history of the origin and establishment in science of the doctrine. While, as heretofore noted in this book, a number of scientists of the past few centuries are shown by their reflections to have had a measure of appreciation of its ultimate effect, and to have applied that effect in their scientific researches, there is no evidence that they ever dreamed of its establishment as a basic fact of science. The real establishment and acceptance of the doctrine dates not much over a half century back. Since that time many scientists have in their researches and writings contributed to its evolution and formation. The experiments of Joule, of England, and the generalizations of Helmholtz, of Germany, are entitled to special mention.

Scientists are naturally and necessarily conservative. So many startling pseudo-scientific facts are announced, that every startling scientific theory, before it is accepted, is submitted to the most careful and crucial tests. No modern scientist will announce a scientific fact as having been demonstrated until the demonstration is complete and fortified with repeated tests of mathematical rigidity, and as long as there remains a phenomenon that does not conform to the supposed theory, acceptance and promulgation will be withheld. It is, therefore, not surprising that the doctrine of Conservation of Energy has been thoroughly intrenched as an established indisputable and accepted fact of science, less than a single generation.

The student of natural science should be warned against the common error of supposing that the discovery of a scientific fact or theory, means demolition of the old theories. The rule is the other way. New theories are additional information to the world, and usually conform to, and are built upon what was known before. Conservation of Energy was generalized from previously known facts conformed to them and reflexively elucidated them, and left them standing clearer than before.

The proof that Conservation of Energy conforms to all other known phenomena of nature has been aided, and hastened by the refinement of scientific instruments by which forms of energy such as heat, electricity, and magnetism can be more delicately measured and determined than ever before, and if instruments for measuring and determining the amount of energy in its various forms were as crude as they were even a single century ago, it is probable Conservation of Energy would still be the undiscovered foundation of all natural phenomena. Let us now consider a few well-known facts which it has been determined positively by the most delicate instruments, prove and illustrate the doctrine of Conservation of Energy.

Resistance to motion, or which is the same thing, motion against resistance, is always accompanied by heat. This developed heat is not always readily perceptible to our sense of touch. A stone, ball or other object thrown through the air has its motion gradually arrested by the air. Heat is developed, but the heat is distributed through so much air and the object thrown is heated so little that this development of heat was not known until scientifically discovered. Where the resistance is friction, the development of heat is quite perceptible, and has always been well known. Suppose a coin be rubbed on a cloth or blotter. Heat is developed both in the coin and the blotter—the more vigorous the rubbing—i.e., the more energy expended, the greater the heat. Science has determined that the developed heat is exactly proportional to the expended energy. Every machinist knows that in turning a tap on a bolt where the threads are rusty so that it turns only with the application of great force, a considerable amount of heat is readily developed. The heat developed is proportional to the energy expended in turning the tap.

A wheel revolving on a spindle will develop heat exactly proportional to the resistance the spindle offers to the wheel turning upon it. Thus, we often see smoke and a blaze rising from the spindles of the car wheels where oil is lacking, and they turn with difficulty.

Every farmer knows that if a buggy wheel turns with difficulty for want of lubrication, or for any other reason, the spindle will heat, expand and lock the wheel, so that it will often either grind out the boxing or slide on the ground. Whereas, if the parts be kept lubricated so that less energy is required to turn the wheel on the spindle, there is no perceptible heat developed, but in all cases heat is developed to some extent, and the heat developed is exactly proportional to the energy necessary to force the revolution.

With heat we can boil water and make steam under a pressure, and with the steam under a pressure we can run an engine, and with the engine make heat by friction, or make electric current that can produce heat. Carry this proposition back to the fuel box, and knowing the amount of heat developed by the burning of a certain quantity of fuel, it is found that, counting the heat that rises in the air through the smoke stack, the heat that is radiated from the boiler, the heat that is carried away in warmed ashes, the heat that exists in the steam after it is exhausted from the cylinder, and all other heat expended whether utilized in driving the machinery or going to waste, the sum total is in every case equal to the heat developed by the fuel box combustion. The most striking thing about all this is that when the steam goes into the cylinder where it is cooled as it expands and drives the pistons, the heat thus lost by the expanding steam is the exact equivalent of the mechanical energy realized against the piston head. Not all of the energy that is realized at the piston head is delivered to the driving shaft. Some of it is lost in the friction of the piston rings wearing against the cylinder lining; some, of course, is lost in friction at the journals connecting with the driving shaft. It is usual in counting engine efficiency to count the amount of energy delivered to the belt, or to the driving shaft, and because of the frictional resistance of the pistons working in the cylinder, there is always found a little discrepancy between the energy represented by the cooling of the steam in the cylinder and the energy delivered to the belt, or the driving shaft.

It is quite surprising how much energy a small amount of heat represents if it could all be converted into the obvious forms of energy. Owing to the great waste suffered in all modern machinery, heat represents much more energy than is ordinarily supposed, in the absence of exact knowledge. One would hardly think it possible that the amount of heat that will raise the temperature of one pound (almost exactly one pint) of water, one single degree (Fahrenheit) is the equivalent of energy required to elevate one pound seven hundred seventy-eight feet high against the force of gravity. Yet, such is the case. This was one of the demonstrations of the immortal Joule. It was he who enabled us to cross the bridge with calculations from mechanical force and motion to heat. He stated the equivalent to be seven hundred seventy-two feet, but more delicate instruments than could be had in his day have shown a slight discrepancy in his calculations, and it is now known to be almost exactly seven hundred seventy-eight feet. Thus, if the Falls of Niagara be considered as being one hundred sixty feet high, the energy developed by the descent is only the equivalent of the heat necessary to raise the temperature of the water about one-fifth of one degree. A modern railroad locomotive does well to realize to the driving rod two per cent of the total energy developed in the fuel box. An ordinary thrasher engine realizes no more than one per cent. The very best steam engines known in large stationary plants do not realize as much as fifteen per cent.

The amount of heat necessary to raise the temperature of one pound of water one degree is taken as a standard for heat measurement, and is known as a British Thermal Unit—nearly always in scientific works abbreviated to B.T.U. The common standard of energy is the amount of energy or work necessary to elevate one pound one foot against the force of gravity. This in scientific works is usually referred to as the foot-pound.

From what is said above it is manifest that one B.T.U. is the equivalent of seven hundred seventy-eight foot-pounds, and vice versa.

The amount of energy must not be confused with the rate of expending energy, or doing work. The horse-power is the common measurement of the rate of delivery of energy or of doing work and is equivalent to 33,000 foot-pounds per minute. It is what one horse can do, and continue doing several hours with reasonable ease. For a short time a horse can exert several horse-power.

Remember, and remember always that heat and electricity are just as much forms of energy as the motion of concrete objects.

We have introduced the above statement of equivalents for the purpose of enabling us to present a few fundamental facts more clearly than could otherwise be done.

Everyone knows that if paddles be revolved rapidly in a vessel containing a liquid, such as a churn, or the like, the liquid will offer considerable resistance to their motion, the amount of resistance depending upon the nature of the liquid, and the rapidity of the motion.

Our scientific instruments have determined the fact to be that the B.T.U. developed in the liquid and on the paddles is the exact equivalent to the foot-pounds of energy required to drive the paddles, i.e., the number of B.T.U. is 778 times the number of foot-pounds.

An engine is run with steam—the engine drives an electric generator. Electricity is developed. This electricity is conducted over a wire to a motor. It is always found that not as much energy can be derived from the motor as is supplied from the generator to the wire. Where is the loss?

It is found that the loss is in the resistance of the wire to the current, and that the wire is warmed—possibly not sufficient to be perceptible to the ordinary sense of touch, and, yet, it is warmed to some extent, and the B.T.U., developed in, and radiated away by the wire, amounts precisely and exactly to the difference in foot-pounds between the energy supplied to the wire at one end of the wire, and the energy supplied by the wire at its other end.

Capillary Attraction is one form of motion by which liquids are elevated and carried considerable distance. The moisture is taken from the earth and carried up the trunks of trees, and out through their limbs to their leaves. This cannot be done without force and energy, but where is the heat? It has been determined and proven that there is an expenditure of heat in doing that work, and that the expenditure of heat is precisely equivalent to the work done. It is hardly believable that there is a loss of heat by coal oil or water, or other liquid performing the work of ascending the wick, and yet, science has determined that that work is only done at the expense of that other form of energy—heat.

If an object falls a distance of twenty feet, and it strikes one end of a lever having two arms of equal length, and at the other end of the lever there be a ball of equal weight, the other ball will be thrown upward twenty feet, less an allowance for the resistance of the air in the descent and ascent, and for the frictional resistance of the motion of the lever. It would throw a ball of twice the weight half the height by adjusting the levers properly. Or, it would throw a ball of one-third the weight three times as high, and so on.

A ball rolling down an inclined plane is found to have a velocity, and consequently a striking force, and an energy equal to that acquired in falling the vertical distance of its descent, due allowance being made for the resistance offered to its rolling motion. It makes no difference whether the incline be great or small, the velocity, the energy are the same as though it had fallen perpendicularly through the same vertical distance.

Instances and illustrations can be multiplied indefinitely. Millions of tests have been made by scientific men, and the basic fact of Conservation of Energy is found true everywhere. That fact is that energy cannot be created. So much as is given is returned in some other form, or else in the form of heat, but in some form, precisely the equivalent is always found to exist.

One of the most beautiful experiments is with the pendulum. Imagine a nail or peg driven into a wall and projecting out—say six inches from the wall. Hang a pendulum four feet long—let the pendulum swing parallel to the wall in the annexed figure. Let "A" represent the point from which the pendulum is suspended. Draw the pendulum back to C, and release it. Its lowest descent in the swing will be at B. It will swing to D, and a line connecting D & C is exactly horizontal, showing that the energy represented by the motion of the pendulum at B was sufficient to elevate it to the point D. Now, on a line on the wall downward from where the nail or peg is driven into the wall, let there be made holes into which a nail or peg can be inserted, and suppose a peg be driven at the point F. If now pendulum be released at C, it will be found that when the cord strikes F the pendulum will swing to the point J, which is on the horizontal line DC. It makes no difference where the interrupting peg or nail be placed, the pendulum will rise to the same horizontal from which it was released. It is said that this was one of Gallileo's experiments. If so, it is another example of the masterly force and originality of his genius, and shows that he subconsciously had some appreciation of the basic facts of the now accepted doctrine of Conservation of Energy.

We believe it is useless to multiply instances further, to illustrate the doctrine of Conservation of Energy, and show the character of proof upon which it rests. There is no fact in nature, but what in the hands of modern science appears to conform to this doctrine. A few years ago when radio-active properties were first discovered it was thought that it was an exception, but even that has been found to conform to this wonderful generalized doctrine.

If the doctrine of Conservation of Energy be true about which there seems to be no doubt, then all hopes of ever attaining Perpetual Motion must cease, for the idea of Perpetual Motion is predicated and has its foundation upon the creation of energy. The mechanism must give more energy than is imparted to it. It must make energy, and this in the light of the generalized truth of Conservation of Energy is an impossibility. We might as well talk about making substance, and the creation of substance, or the creation of energy either one is not an attribute of man. It is an attribute to be accredited only to the infinite, and can not be conceived as an attribute of the finite.

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