The Mechanical and Electrical Oscillators of Nikola Tesla

"Obedience, Bane of all genius, virtue, freedom, truth, Makes slaves of men and of the human frame A mechanized automaton." — Shelley.

Thus has it been with nearly all projectors. Pioneers into the unknown have felt their power when they saw the unlimited stretch before them.

A great man upon being asked how he managed to accomplish more than others, replied, "I just do a little bit more than anybody else has done."

It has been said that a genius is one who takes infinite pains, and that he is born, not made. These statements hardly seem to reconcile themselves to each other, unless it be, the power of intense concentration and of almost limitless energy is a divine gift.

Incidents amount to nothing unless they are recognized and appreciated. The humming tea-kettle with its latent power was the vision on the wall to him who first recognized its importance. The frog legs of Galvani was but an accepted hint to those who laid the foundation of our grand and growing science. As in the life of man, where his advent is a bright spot in his history, so these pioneer discoveries were the beacons which showed the way to higher and more useful things.

We are almost tempted to change the words of the wise and worldly Solomon, who said, "There is nothing new under the sun," to, "There is nothing old under the sun." All fields present vast possibilities in their cultivation. The fruits to be obtained from these rich and generous soils are only to be procured by those who work to gather them.

Launched as we are into. the realms of imaginative science, we cannot help but realize that it is the severely practical which, in the end; advances us most. Progress, strong and steady progress, having the inertia of a master mind, is full of possibilities. He who is free, untrammeled and backed with a store of the essentials that have gone before; he who lives in a world of his own and has a strong mind in a strong body, is bound to produce that which will startle plodders in the beaten paths well worn by those, the multitude gone before.

Few are they who can say: "I am as free as Nature's first made man."

He then who profits by the experience of others and follows his own line of thought approaches a certain state of freedom; but it is merely comparative.

"On their own merits modest men are dumb."

Some men have said that while Nikola Tesla has produced wonderful results, he has given the world but little of practical value. Those who have been careless enough to make this statement have evidently not realized that of which they spoke. Was the voltaic pile the dynamo of to-day? Was the æolipile the steam engine of the present? A little reflection will show us that Mr. Tesla is a pioneer; but above all, that he is essentially a practical and efficient economist. He has eagerly and unceasingly searched for radical defects in existing machines. He has patiently sought for losses in efficiencies, which, to the ordinary experimenter, were considered a matter of course. His work during the last few years, as the public has imagined, was in the line of effects due to currents of high frequencies, and a method of transmitting intelligence by means of electrical waves to almost limitless distances on the earth. And the public have been right; but little did they imagine what this man had in store for them.

A few sceptics may raise their eye-brows and say, "What does all this amount to?" These few may be quickly silenced by showing to them results. Could anyone ask for more? But to those who are impatiently waiting and who have a sincere belief, based upon previous experiences, that "the mountain will not bring forth a mouse, but that out of it a greater mountain shall spring forth," I will say: Listen to a simple tale which we will call "The History of an Invention."

On Friday evening, August 25, Nikola Tesla startled the assembled scientists at the World's Fair with what he chose to call his mechanical and electrical oscillators. None knew what he was going to see when he read the title of this lecture. None knew of the possibilities which would be presented by this radical departure in the twin sciences, steam and electrical engineering. And here is the way in which this last child of Mr. Tesla's brain was conceived.

While Mr. Tesla was working on his motor he realized the need for absolute synchronism, and this we will call Necessity No. 1.

In his extensive and varied work in high frequency currents, he obtained exceedingly small efficiencies, due to the fact that the north and south poles of his magnets were, in many cases, as close as one-sixteenth of an inch apart, and the wires which wrapped them were one-thirty-second of an inch in diameter. Magnify these conditions and the practical electrician will readily see how the efficiency will be reduced to a minimum. This led Mr. Tesla to think that the remedy for this defect would be the discarding of iron, thus making his armature entirely of copper; and to this we will give the name, Necessity No. 2.

His thoughts were not alone on electrical engineering. The losses from the furnace to the dynamo stood out in bold relief in the intricacies of his thoughts.

One of the most useful devices to mankind is the crank, that means of changing a reciprocating motion to a motion of revolution. But in that change, oh what a loss is there! That ponderous thing — the flywheel of the steam engine — melted into thin air over 50 per cent. of the power from the piston. We have a maximum resistance, practically an infinite resistance, at two points, each co-incident with the axis of the piston head, and this resistance diminishes until we obtain two points which have a minimum resistance, and in this passage from the infinitely great to the almost infinitely small we recognize our loss.

In our mammoth engines it requires special buildings to construct the separate parts, and then think of the huge masses of metal — necessary evils to the heretofore existing steam engines. Advances have been made, it is true, and a 12 per cent. loss due to belting has been saved by the direct coupled dynamos. But before the advent of the oscillator few attempts were made to reduce this sinful waste from the piston to the flywheel, and this we will call Necessity No. 3.

Here then are three great necessities, and if we may believe the old adage, we should expect great children from these great mothers; nor have we any cause to be disappointed.

Although Mr. Tesla's mechanical and electrical oscillators are not, as yet, practically perfect, the theories stand and they are obviously reasonable and correct.

We first will deal with the mechanical oscillator. We shall see how this device does away completely with those accessories called the flywheels, regulators and governors. We shall see how the ponderous pile of metal to be moved may be reduced to one-fortieth its original bulk, and still have its efficiency maintained.

The mechanical oscillator briefly described may be pictured by imagining an exceedingly short stroke piston, and port valves which extend completely around the cylinder. The oscillations of this short stroke piston may be varied in frequency by the resistance encountered. In practice these oscillations need not be more than from 40 to about 90 per second, and since the length of the movement of the piston is slight, its lineal velocity is hardly more, if equal, to that of an ordinary Corliss engine. Here though is where the beauty of the oscillator is apparent. It is perfectly regular in its movements.

To give a better idea of its method of motion we can compare it to a swinging pendulum which, though we may increase its velocity at any point of its swing, its time of oscillation is not varied a thousandth of a second, provided, of course, that nothing but gravity and the uniform surrounding medium, the air, affects it. This is exactly the case with the oscillator; if it is resisted at any point of its path, or if the steam pressure is varied, it makes no difference in the time of its "swing," and we thus have an oscillator which may be made absolutely synchronous with other oscillators, by the addition or subtraction of definite weights. Necessity number one is thus filled.

It will be seen also that necessity number three is here done away with, for our motion is simply a reciprocating one, and we need no conversion to a motion of revolution. Instead of having a generator whose armature revolves, we have one which accommodates itself to this reciprocating motion, and whose armature or field magnets, as the case may be, oscillates in a straight line. Some, perhaps, will say that this is nothing new. Nothing new is claimed for it; it is simply an improvement — an improvement which accommodated itself to the existing conditions required by the mechanical oscillator.

Let us take, for instance, the case where the armature is directly and rigidly connected with the oscillating piston. A simple form of the field magnets would be represented by two iron tubes placed concentrically — the inside diameter of one twice the outside diameter of the other — and imagine both these tubes to have such thick walls that the inside tube becomes practically a rod, the outside tube having the same Let the farther end of these thickness. two tubes be covered by a mass of iron, and immediately underneath this covering, around the inside tube, be wrapped the field magnet coils. Upon the passage of a current an intense field will be produced, and backwards and forwards in this field, near the other extremity of the two tubes, does a simple coil of wire oscillate with a clearance of but a hundredth of an inch on each side. This coil of wire is the armature, whose axis is co-incident with the axis of the mechanical oscillator. Thus we see flywheel and governor are thrown aside; a simple efficient steam engine is produced and hardly a simpler dynamo could be conceived. Delicate and absolutely accurate mechanical construction is not so necesssary as in the case of other machinery of its kind. No larger tool than a six inch lathe is necessary to turn out a 100 horse-power oscillator. Owing to its small size the losses due to heating large masses of iron are entirely done away with.

Here we have two new devices constructed on sound scientific principles. It rests with the mechanical engineer to perfect the minor details of the mechanical construction of the mechanical oscillator, and with the electrical engineer to give the finishing touches to the electrical oscillator. There is a great future before them.

Who shall they or he be?

It needs no vivid imagination to hear the answering echo of this question as it resounds in the minds of the true lovers of Nature and Progress; for who can possibly know more about this great improvement in steam and electrical construction than he, the father, who has given life to and tended these oscillators with most intense solicitude through the progress of the invention? And although the most prominent quality which all have observed in Nikola Tesla is his true modesty, his apostles should be allowed to place his name alongside of those of Franklin, Faraday and Henry.

JULIAN A. MOSES.