Perpetual Motion as used in this book is to be taken in its conventional, and not in its strict literal sense. The strict literal analysis of the two words implies unceasing motion. Of this we have many illustrations—the tides, the waves of the ocean, the course of the earth around the sun, and in the movements of all heavenly and astronomical bodies. In fact, it is difficult to conceive in a strictly scientific sense of any substance having an entire absence of motion.

Perpetual Motion as used in this book means what it is usually understood to mean—Self-Motive Power—a machine that furnishes the power to keep its parts going as a machine. In this sense Perpetual Motion has always engaged the minds of many, many people—and what is more natural? As soon as a boy begins to take an interest in moving parts of machinery, vehicles, locomotives, and what not, he perceives that the application of power results in the motion of bodies, and again that bodies in motion are productive of power. A wheel moved by muscular, or other mechanical power, is made by machinery to elevate water, and elevated water can be made in descending to run machinery. The windlass, or other wheel, turned by applied force, lifts buckets from wells—raises stone, and elevates heavy bodies, if desired. Heavy bodies descending can be, and are used through means of machinery to make machinery run.

A great many similar illustrations could be given. What, then, is more natural than that a boy with an active mind who is at all mechanically turned, as most boys are, begins to wonder why, if wheels lift stones, and if stones descending make wheels run, cannot a machine be made that will lift stones, or other weights, and in turn be run by the descent of the lifted stones, or other weights? Why, if the turning of wheels lift water, and if descending water makes wheels go, should not an adaptation be made by which the same machine will elevate water, and be run by the descent of the elevated water?

That it cannot be done is now the consensus of opinion of all technically trained mechanics, but, that it can not be done, and why it can not be done, is sure not to occur to the boy, nor to the man who has only a strong natural mechanical sense to guide him, and has not the advantage of technical training.

Again, it is well known that many, many men have spent considerable sums of money and given hours and hours, and days, and months, and years of close and careful thought, and experiment to the production of a machine that will accomplish Perpetual Motion, and that many have announced to the world that they had succeeded in its accomplishment, but that all their devices so far have turned out failures.

It is to no purpose to tell the Perpetual Motion worker that he is seeking to attain the impossible; that the attainment of self-motive power has been demonstrated to be an impossibility. He will answer, or, at least, he will reason to himself that many things once pronounced impossibilities and claimed to be so demonstrated, have since been attained. The Perpetual Motion worker is usually a person of active intelligence, and being enamoured of mechanical projects is likely to read extensively along mechanical lines, and knows as every well-informed person knows, that there are many instances in the history of the discovery and development of the most important mechanical inventions and scientific discoveries where the persistent efforts of so-called enthusiastic dreamers and cranks finally triumphed over the settled and conventional "impossibilities" of dignified scientists.

When, less than a century ago, it was proposed to propel a ship across the Atlantic ocean by steampower, Ignatius Lardner, a scientific teacher, lecturer and interpreter of real note and merit wrote a book "demonstrating" the physical impossibility of a vessel carrying enough fuel to propel itself through that distance of water. The book was actually printed, but was scarcely off the press until the first steamship had successfully crossed the Atlantic with steampower, and steamed triumphantly into port.

After communication by electric telegraph was well established and had been in successful commercial use for decades, it was proposed to converse by long distance over a wire. The idea was hooted and declared impossible, and it did seem so, and yet today, there is scarcely a farm house in the nation but what has an instrument by which the occupants can talk over wires not only to their near-by neighbors, but to remote cities.

Prof. Samuel P. Langley, less than two decades ago undertook in a thoroughly scientific manner to accomplish what is called "heavier than air flight." His scientific ideas on the subject were entirely correct, but he did not have the advantage of engine refinement as it is known today, by which high energy development can be attained with an engine or motor of small weight. Nevertheless, Prof. Langley succeeded in flying a considerable distance, and in fact, made a number of successful demonstrations of the physical possibility of heavier than air flight. Prof. Simon Newcomb, who is to be ranked as the greatest astronomer, mathematician and scientist the United States has ever produced, and with the possible exception of Benjamin Franklin, the most original thinker along scientific lines, wrote an article which was published generally in scientific journals, in which he warned Prof. Langley of the folly of his attempts, not claiming, however, the scientific impossibility of heavier than air flight, but claiming that it could never be of any real practical value; that the instability of the air, etc., limited flight by man to a daredevil show performance. A child then born would now be scarcely grown, and yet, aeroplanes are in use in every civilized country in the world for observation and military purposes, and even for carrying mail to places not otherwise easily accessible.

Thousands of flights are undertaken every day with the confident expectation of a successful trip and return. How many, many boys and mechanics, prior to the achievement of human flight, have been attracted by the problem, only to have their ambitions and dreams discouraged and suppressed by being told that the scientific world knows that human flight is impossible—"God made man to walk on the ground, and the birds to fly, and if Nature had intended that we should fly we would have been equipped with wings," and probably to be dubbed "Darius Green," as a reminder of the inglorious fate of the pseudo hero of that name in Trowbridge's clever and immortal poem about Darius Green and his Flying Machine.

The announcement of the discovery of rays by means of which views may be made and photographs taken through substances supposedly opaque to all light rays was scouted as a ridiculously visionary dream; but the discoverers were not dismayed by scout and ridicule, but persisted in their dreams and enthusiasm. There is not a village of any considerable size in the civilized world but has its X-Ray Machine by which foreign substances in the flesh may be viewed and photographed and located with exactitude, fractures examined and all surgical operations aided to the benefit and health and recovery of the sick and wounded. Mankind is the recipient of the benefits resulting from the fact that enthusiastic cranks were not deterred by ridicule and supposed demonstrations of their folly. The above are only a few of the many like instances recorded in scientific progress. While not accurately true, and while less true during the last two decades than formerly, it is, nevertheless, a general truth that scientific progress has been made in spite of, and in the face of discouragement and ridicule from the multitudes who were destined to be benefited by the discoveries made by the persistent so-called cranks.

These facts are all well known to the Perpetual Motion enthusiast. It is, therefore, of no avail to tell him that the scientific world has pronounced his aspirations and attempts but dreams, and that Perpetual Motion workers are by the scientific world denominated cranks.

If it be admitted that Perpetual Motion is, as scientific men tell us, a chimerical dream, it is still to be very greatly doubted if the world at large is to be benefited by dissuading minds from working on the problem. There is no doubt that many persons who have become more intensely interested in mechanics by thinking and working on the problem of Perpetual Motion, have thereby been lead to study more and more generally into mechanical subjects, and became not merely tyros, but useful men in various mechanical pursuits. Many doubtless have followed mechanical subjects to which they were introduced by labors toward Perpetual Motion, to the making of useful and valuable inventions and discoveries.

Notwithstanding the fact that a countless number of devices for the attainment of Perpetual Motion have been proclaimed and exhibited, it is to be supposed that those actually proclaimed and brought to light constitute but an infinitesimally small proportion of those actually made. It is to be supposed that the Perpetual Motion worker has some sense, and that the great majority of them before proclaiming his apparatus would want to know himself that it was not a failure, and would not, when ushered before the public, bring upon him humiliation and jeers. It is to be believed that in nearly every instance the produced device was tested before being proclaimed and ushered into the light of day. It goes without saying that all that were so tested were failures, and were never heard of except by the inventor and a very few intimate friends or co-laborers. Those that have been heralded to the world represent only that small proportion where over-confidence in the operation, or a disregard for the truth, or some other unexplainable something caused the inventor and his friends to make the announcement and disclosure of the device before the test.

It is almost impossible to conceive of a person of any intelligence exposing himself to the ridicule resulting from the failure of a pompously heralded device, when a simple test would have saved the exposure, and yet the civilized world has been filled with Perpetual Motion devices proclaimed and heralded with trumpet blast, which, when tested, "didn't work."

It is not, however, the purview, or purpose of this book, to incite people to work on the problem of Perpetual Motion, neither is it its purview or purpose to dissuade them from it.

In the works of Mr. Dircks, mentioned in the preface of this work, the devices for Perpetual Motion are classified somewhat with reference to the time each was produced. In some instances with reference to whether or not patents were applied for and obtained, or as to the source of information concerning them.

A careful examination of the devices presented in Mr. Dirck's two works, and of those, information concerning which has been obtained elsewhere, leads the author to believe that nothing is to be gained by an attempted classification along those lines. In countless instances Perpetual Motion seekers of different races and living in separate countries, and, indeed, on different continents, centuries apart, have sought the attainment of Perpetual Motion by practically the same devices, and inventor after inventor has brought forth alleged inventions depending upon precisely the same underlying mechanical principle.

The author has attempted to classify the various devices presented in this book according to the underlying mechanical principles upon which the inventor chiefly relied for the success of his invention. Even this classification is extremely difficult and not well distinguished. Many of them, indeed most of them, depend for their success upon more than one mechanical principle, and the classifications thereby inevitably intermingle and overlap what otherwise would be their distinguishing boundaries. Still it is believed by the author that it is the best that could be adopted, and that no better or clearer classification is possible than the one here presented.

The various devices are classified by the author under the following heads:

Devices by Means of Wheels and Weights.

Devices by Means of Rolling Weights and Inclined Planes. Hydraulic and Hydro-Mechanical Devices.

Pneumatic Siphon and Hydro-Pneumatic Devices.

Magnetic Devices.

Devices Utilizing Capillary Attraction and Physical Affinity.

Liquid Air as a Means of Perpetual Motion.

Radium and Radio-Active Substances Considered as a Conceived Source of Perpetual Motion.

Perpetual Motion Devices Attempting Its Attainment by a Misconception of the Relation of Momentum and Energy.

to which is added—

"A Discussion of the Alleged Inventions of the very eminent Edward Sommerset, Sixth Earl and Second Marquis of Worcester, and Jean Ernest Eli-Bessler Orffyreus.

Also—

"A Discussion by the Author of the 'Doctrine of Conservation of Energy, and Its Relation to the Possibility of Perpetual Motion.'"

And—

"A Discussion by the Author of 'Will Perpetual Motion Ever Be Accomplished?'"