Long before the Christian era the Chinese used pivoted magnetic needles to indicate absolute direction to them; but that they possessed or had invented the mariner's compass, there is considerable doubt. The history of the invention of the mariner's compass has not yet been written. It is not known when, or where, or by whom it was invented.

It is well-known, however, that the mariner's compass was in use in the Mediterranean Sea in the early part of the fifteenth century A.D. Guided by it, the navigators of that day pushed far out from land.

The first great navigational feat that followed the invention of the compass was that performed by the Portuguese, Bartholomew Dias, who conceived the idea of reaching India by going around Africa, and sailed down the west coast of Africa as far as its southern end, later called the Cape of Good Hope. It was a tremendous undertaking, and it had tremendous results; for it demonstrated the possibilities of great ocean voyages, proved that the road to India was very long, and led to the expedition of Columbus, six years later. It was also a great invention, both in brilliancy of conception and excellence of execution, although Dias did not reach India.

The second great navigational feat was performed by Christopher Columbus in 1492. Before that time it was conceded by most men of learning and reflection that the earth was spherical; and it was realized that, if it was spherical, it might be possible by sailing to the westward to reach India, the goal of all commercial expeditions in that day. Columbus is not to be credited with the first conception of that possibility.

The invention of the gun was followed by the invention of printing in 1434, and this by the discovery of America in 1492. These three epochal occurrences started the new civilization with a tremendous impetus. This impetus was immediately reinforced by the voyage of the Portuguese Admiral, Vasco da Gama, around the Cape of Good Hope to India in 1497–1498, and the circumnavigation of the globe by Ferdinand Magellan in 1519–1522.

The immediate practical influence of da Gama's feat was almost to kill the commerce of the cities of Italy and Alexandria with India by way of the Red Sea and the Indian Ocean, and to transfer the center of the sea-commerce of the world to the west coast of Europe, especially Portugal. Near the west coast it has rested ever since; though but little of it stayed long with Portugal.

While Magellan's voyage was not quite so important as the discovery of America, it was not immeasurably less so; for it set at rest forever the most important question in geography,—was the earth round or not? The voyage of Columbus had not answered it, because he returned by the same route as that by which he went. But Magellan started in a southwesterly course, and one of his ships again reached home, coming from the east. The Victoria had circumnavigated the globe! Only eighteen men and one ship returned. The other ships and the other men had perished. Magellan himself had been buried in the Philippines.

The news of Magellan's great exploit and the stories that came to Europe of the riches beyond the sea, resulted soon in an idea coming to the mind of Hernando Cortez, the development of that idea into a concrete plan, and the making of a complete invention. This was a plan by which he should head an expedition to a certain part of the New World, and "convert" the heathen dwelling there; doing whatever killing and impoverishing and general maltreatment might be found to be convenient or desirable. The invention worked perfectly; some half-savage Indians of what we now call Mexico were "converted," many were killed, and untold treasure was forcibly obtained.

The success of this invention was so great that Francisco Pizarro was inspired to copy it, and to try it on some Indians in a country that now we call Peru. Whether Pizarro improved on Cortez's scheme, or whether the conditions of success were better need not concern us now: the main fact seems to be that Pizarro was able to convert and kill and impoverish and generally ruin more effectively than Cortez.

Following Cortez and Pizarro, many expeditions sailed from Spain to the West Indies, Central America and South America, and carried out similar programs. The two principal results were that those parts of the world were soon dominated by Spain, and that the people of Spain received large amounts of gold and treasure. The main result to them was that they succumbed under the enervating influence of the artificial prosperity produced, and rapidly deteriorated. By the end of the hundred years' period after Columbus discovered America, Spain was clearly following the downward path, and at high speed.

One of the early results of the invention of printing was an increased ability of people separated by considerable distances to interchange their views; and a still greater though allied result was an increased ability of men of thought and courage to impress their thoughts upon great numbers of people. At the time when printing was invented, the Church of Rome had ceased to dominate European nations as wholly as it had done before; but it exercised a vast power in each country. This was because of its prestige, its hold on the clergy and the Church property, and its authority in many questions connected with marriage, wills, appointments, etc. This was resented, but impotently, by the various sovereigns.

It was realized also (and it came to be realized with increasing clearness toward the end of the fifteenth century) that there were many grave evils and scandals in the Church, even in the highest quarters. The printing-press lent itself admirably to the dissemination of views on this matter: so that there gradually grew up a strong and widespread feeling of discontent. But despite considerable friction as to the limits of their respective functions, the Church and the State were so intimately allied in every country, and each realized so clearly its dependence on the other, that no movement of any magnitude against even the acknowledged evils had been able to gain ground. No man appeared who was able to conceive and execute a plan that could successfully effect reform.

But such a man appeared in the year 1517, whose name was Martin Luther. He was a poor monk; but a knowledge of virtually all there was to know lived in his mind, coupled with imagination to conceive, constructiveness to plan, and courage to perform. In that fateful year, 1517, the Pope sent agents through the world to sell "indulgences," which remitted certain temporal punishments for sin, in return for gifts of money. The agent who was commissioned for Germany carried out his work with so little tact and moderation, that he made the granting of indulgences seem even a more scandalous procedure than it really was. Luther had been preaching the doctrine of a simple following of the teachings of the Savior, and deprecating a too close adherence to mere forms and ritual. He now seems to have conceived a clean-cut plan of effective action; for on the evening before the indulgences were to be offered on All Saints Day, in the Church of Wittemberg, Luther nails on the door his celebrated ninety-five theses against the sale. The printing-press reproduced copies of these in great numbers throughout Germany. A definite sentiment antagonistic to the indulgences developed rapidly, and a general movement toward the reform of the abuses in the Church took shape. Luther was threatened with excommunication by the Pope in 1520, but he burned a copy of the "papal bull" in a public place on December 10 of that year.

The emperor of Germany convened a meeting of the Diet at Worms in 1521, at which he exerted all his powers to make Luther retract: but in vain. So great a following did Luther now have that, though the emperor put him under ban, and all persons were forbidden to feed or give him shelter, he was cared for secretly by men in high position, until he voluntarily came out of hiding, and appeared in Wittemberg. The emperor called a meeting of the Diet at Spires in 1526, and another meeting in 1529. Both meetings had for their object the suppression of the movement begun by Luther. It was against a decree made by the second Diet that certain high officials and others made the famous protest, that caused the name to be affixed to them of Protestants. This name has been perpetuated to this day.

As is well known, the movement resulted, after nearly a hundred years of disturbed conditions, in a series of wars, called "The Thirty Years' War" that began in 1618, and ended with the Peace of Westphalia in 1648. This Peace marked the end of the Reformation period, and resulted in establishing Protestantism in North Germany, Denmark, Norway, Sweden, England and Scotland.

The influence of Luther's conception with its subsequent development was thus definite, widespread and profound, even if regarded from a merely religious point of view: but the influence it had on religion was only a part of its total influence. In words, the protest was against certain abuses in the Roman Church; but in fact it was against a domination exercised over the minds and souls of men. Luther's influence was in reforming not only the Roman Catholic Church and the practice of the Christian religion throughout Europe, but also the conditions under which men were allowed to use their minds.

While the inventions in mechanism, religion, etc., which we have just noted were going on during the fifteenth and sixteenth centuries, others were going on in the realm of science. The movement was begun about 1507 by a young man named Nicolas Copernicus, who was executing the dissimilar functions of canon, physician and mathematician in the little town of Frauenberg in Poland. Copernicus at this time was thirty-four years old, but he had even then devoted the major activities of his mind to astronomy for several years. Naturally, his efforts had been devoted to mastering whatever of the science then existed. The efforts of most people in dealing with any subject end when they have gone thus far—and very few go even thus far. But Copernicus noted that, while the Ptolemaic System (suggested, though probably not invented by the Egyptian king) was the one generally accepted, it did not account for many of the phenomena observed; that none of the other systems that had been suggested afterward explained matters more satisfactorily, and that no one of the systems was in harmony with any other.

Thereupon this daring young man conceives the idea of inventing a system of astronomy himself, in which all the movements of the heavenly bodies should be shown to be in accordance with a simple and harmonious law. Seizing on this idea, he proceeds at once to develop it; and he works on it until death takes him from his labors in 1543 at the age of seventy. The whole civilized world had virtually accepted the Ptolemaic Theory,—at least, the part of it which assumed that the earth was the center of the universe, the sun and stars and planets revolving around it. Copernicus invented the theory that the sun was the center, that the earth and the other planets revolved around it, and that the earth revolved on its own axis once in twenty-four hours. So great was the insistence of the religious bodies in adhering to the Ptolemaic Theory, so set were the minds of all men of high position on it, that though Copernicus wrote a book expounding his own theory, he did not think it wise to publish it. He seems to have completed the book in about 1530. He did not publish it till 1543. Just before its printing was finished, Copernicus was taken ill. The first volume was held before him. He touched it and seemed to realize dimly what it was. Then he relapsed into torpor almost immediately, and soon died.

It is interesting to note that Copernicus was not the first to conceive the idea that the earth turns on its own axis, or that the earth revolves around the sun, any more than Bell was the first to conceive the idea that speech could be transmitted by a suitable arrangement of magnet, diaphragm and electric circuit. But Copernicus was the first to invent a system of astronomy that was like a machine. It was a usable thing. It could be made to explain astronomical phenomena and predict astronomical events correctly.

It may be well to remind ourselves again that no application for patent will be granted by our Patent Office unless the invention is described and illustrated so clearly and correctly that "a person skilled in the art can make and use it;" and to realize that this admirable phraseology may be utilized to distinguish any other novel endeavor of man entitled to be called an invention from any other not so entitled; for no system, no theory, no religion, no scheme of government, regardless of how attractive it may be, is entitled to be called an invention, unless, like the Copernican System, "a person skilled in the art can make and use it."

Shortly after Copernicus, came Johann Kepler, who was born in WÜrttemburg in 1571, and died in 1630. He had been a pupil of Tycho Brahe, who did not succeed in making any great invention or discovery, but who did collect a great amount of data. Utilizing these, Kepler devoted many years to the study of Copernicus, and tried to invent a system which would explain some facts of astronomy that the system of Copernicus did not explain, notably the non-uniform speed of the planets. The main result of his labors was the famous Kepler's Laws, which were

"1. The orbits of the planets are ellipses having the sun at one focus.

"2. The area swept over per hour by the radius joining sun and planet is the same in all parts of the planet's orbit.

"3. The squares of the periodic times of the planets are proportional to the cubes of their mean distances from the sun."

These three discoveries, enunciated in three interdependent, concrete laws, constituted an invention which, while it was merely an improvement on Copernicus's, was so great an improvement as almost to make the difference between impracticability and practicability. Without this improvement, astronomy would not be what it is, navigation would not be what it is, the regulation of time throughout the world would not be what it is, and the present highly intricate but smoothly running machine of civilization could not exist at all, except in a vastly inferior form. The machine of civilization is dependent for its successful operation on the good quality and correct design of every other part. So is every other machine; for instance, a steam-engine.

The Copernican System was not recognized for more than a century. It was, in fact, definitely rejected, and people were subjected to punishment and even torture for declaring their belief in it.

One of the amazing facts surrounding Copernicus's invention was that he carried on his observations with exceedingly crude appliances. The telescope had not yet been invented.

Who invented the telescope is not definitely known; but it is probable that both the telescope and the microscope (compound microscope) were invented by Jansen, a humble spectacle-maker in Holland. Both inventions were made about the year 1590, and were of the highest order of merit from the three main points of view,—originality, completeness and usefulness. Few inventions more perfectly possessing the attributes of a great invention can be specified. The originality of the conception of each seems unquestionable; the beautiful completeness of the embodied form of each was such that only improvements in detail were needed afterward; and, as to their usefulness, can we even imagine modern civilization without them both?

The interesting fact may now be called to mind that, although many men who lived in Jansen's time were loaded with honors and fame and wealth and glory, the inventor of the telescope and the microscope received no reward of any kind that we know of; and his fame has come to us so imperfectly that we are not even sure that Jansen was his name.

The man usually credited with the invention of the telescope is Galileo, though Galileo himself never pretended that he invented it, and though historical statements are clear that he heard that such an instrument had been invented, and then designed and constructed one himself in a day. It would be interesting to know just how much information Galileo received. It seems that his information was very vague. If so, a considerable amount of inventiveness may have been required, besides a high order of constructiveness. But the mere fact that Galileo knew that such an instrument had been invented caused his mental processes to start from an image put into his mind by an outside agency and not from his own imagination. Galileo's work did not begin with conception, and therefore it was not an invention.

Galileo was one of the foremost and most ardent supporters of the Copernican Theory; and it was on his skilful and industrious use of the telescope in making observations confirming the theory that his fame mainly rests. As late as 1632, nearly a century after Copernicus's doctrine had become known, Galileo was compelled by threat of torture to recant, and was condemned to imprisonment for life.

The influence of inventions on history has been greater and more beneficial than that of any other single endeavor of man. Yet most inventions have been resisted. The invention of Copernicus was resisted for more than a century by the organization commanding the greatest talent and character and learning that the world contained.

The extraordinary access of mental energy in Europe about the beginning of the seventeenth century is illustrated by another invention virtually contemporaneous with those of Copernicus and Jansen, and also in the line of mathematical research. This was the invention by Baron John Napier of logarithms.

It was a curious invention—an invention the like of which one cannot easily specify; for the thing invented was not a material mechanism, or a theory, or anything exactly like anything else. It is difficult to classify a logarithm except as a logarithm:—yet Napier did create something; he did make something exist that had not existed before; he did conceive an idea and embody that idea in a concrete machine. That machine, in the hands of a man who understood it, could supply extraordinary assistance in making mathematical calculations, especially calculations involving many operations and many figures, as in astronomy. It has been in continual use since Napier invented it, and is used still. In order to indicate the simplicity and the value of Napier's invention, it may assist those who have forgotten what a logarithm is, or who have been so fortunate as never to have been compelled to study about them, to state that logarithms are numbers so adapted to numbers to be multiplied, divided, or raised to any power, that one simply adds their logarithm, subtracts one logarithm from the other or multiplies or divides a logarithm by the number representing the power, and then notes in a table the number resulting, instead of going through the long process of multiplying, dividing, squaring, etc. Of course, in the case of small numbers, the use of logarithms is not only unnecessary but undesirable; but in the case of the long numbers used in astronomy, and even in navigation, logarithms are inexpressibly helpful and time-saving. The mental feat of Napier consisted in conceiving the idea of accomplishing what he subsequently did accomplish, and then constructing and producing the "logarithmic tables" that made it possible.

Another indication of the new intellectual movement in Europe was the experiments, deductions and inventions of William Gilbert, an English physician, who lived from 1540 till 1603. According to the use of the word invention followed in this book, only two actual inventions can be credited to Gilbert, that of the electroscope and that of magnetization. Gilbert's work was valuable in the highest degree, more valuable than that of most inventors; and yet it was more inductive and deductive than inventional. It is not the purpose of this book to suggest that invention has been the only kind of work that men have done which has had an influence on history; and the work of Gilbert gives the author an opportunity to emphasize the value of certain work which is not inventional. At the same time, the author cannot resist the temptation of pointing out that Gilbert's work was original and constructive, that it hovered around the borders of invention, and that it did more to assist the inventors of the electric and electro-magnetic appliances that were soon to follow, than the work of almost any other one man.

The full influence of Gilbert's work was not apparent for many years; not, in fact, until the discoveries and inventions of Volta, Galvani and Faraday showed the possibilities of utilizing electricity for practical purposes. Then the facts which Gilbert had established, and the discoveries built upon them afterward, were the basis of much of the work of those great men, and of the vast science of electrical engineering that resulted.

The inventions made before the opening of the seventeenth century A.D., wonderful as they were, were quite widely separated in time, and seem to have been wholly the outcome of individual genius, and not the result or the indication of any widespread intellectual movement. But soon after it opened, the influence of printing in spreading knowledge became increasingly felt, and inventions began to succeed each other with rapidity, and to appear in places far apart.

In the beginning of the seventeenth century, certain writings appeared in England that took great hold on the minds of thinking men, not only in England, but throughout Europe. The name of the author was Francis Bacon.

It would not be within the scope of this book even to attempt to analyze the philosophy of Bacon, to differentiate between it and the philosophy of Aristotle or any other of the great thinkers of the world, or to try to trace directly the influence of Bacon's philosophy on his own time and on future times. It is obvious, however, that Bacon invented a system of inductive reasoning that assisted enormously to give precision to the thoughts of men in his own day, by convincing them of the necessity of first ascertaining exact facts, and then inferring correct conclusions from those facts. This seems to us an easy thing to do, looking at the matter in the light of our civilization. But it was not easy, though Bacon's high position gave him a prestige exceptional for a philosopher to possess; and this smoothed his way considerably. Men had not yet learned to think exactly. The efforts of even the great minds were of a groping character; and fanciful pictures made by the imagination seem to have intertwined themselves with facts, in such a way that correct inferences (except in mathematical operations) were hardly to be expected. Bacon insisted that every start on an intellectual expedition should be made from absolutely indisputable facts.

The first effect of such teaching was to make men seek for facts. Not long afterward, we find that many men were making it the main business of their lives to seek for facts from Nature herself. This does not mean that men had not sought for facts before from Nature, or that Bacon alone is to be credited with the wonderful increase in the work of research and investigation that soon began.

Bacon's principal book was published in 1620, and called the "Novum Organum," or "the new instrument." It was obviously an invention, for it was a definite creation of a wholly new thing, that originated in a definite conception, and was developed into a concrete instrument. That Bacon so regarded it is evident from the title that he gave it. Furthermore, he described it as "the science of a better and more perfect use of reason in the investigation of things and of the true aids of the understanding." Bacon was a patient of Dr. Harvey, who discovered the circulation of the blood; and it would be strange indeed if Bacon's philosophy did not give to Harvey a great deal of guidance and suggestion that furthered his experiments.

William Harvey discovered the fact that the blood circulates in the bodies of living animals. This declaration stated by itself would convey to the minds of some the idea that Harvey discovered it, somewhat as a boy might discover a penny lying on the ground. The first definition of the word discover in the Standard Dictionary is "to get first sight or knowledge of"; so that the mere announcement that an investigator has "discovered" something gives to many people an incorrect idea of his achievement. Harvey discovered the fact of the circulation of the blood after years of experimentation and research on living animals, and by work of a most laborious kind. His conclusions were not accepted by many for a very considerable period; but he was fortunate, like Bacon, in holding a position of such influence and prestige, that he escaped most of the violent opposition that inventors usually meet.

Harvey's discovery did not of itself constitute an invention; but the embodiment of that discovery in a concrete theory, so explained "that persons skilled in the art could make and use it," did constitute an invention of the most definite kind. The whole influence of that invention on history, only a highly equipped physician could describe; but, nevertheless, one may feel amply justified in stating that its influence on the science and practice of surgery and medicine, and on the resulting health of all the civilized nations of the world, has been so great as to be incalculable.

A contemporary and acquaintance of Harvey was Robert Boyle, one of the most important of the early scientific investigators, who was an avowed disciple of Bacon, and followed his methods with conscientious care. His work covered a large field, but it was concerned mostly with the action of gases. He is best known by "Boyle's Law," which is usually expressed as follows: "When the volume of a mass of gas is changed, keeping the temperature constant, the pressure varies inversely as the volume; or the product of the pressure by the volume remains constant." While it has been found that this law is not absolutely true with all gases at all temperatures and pressures, its departure from accuracy are very small, and these are now definitely known. With certain tabulated corrections, this law is the basis on which most of the calculations for steam engines, air engines and gas engines are made. It is usually expressed by the formula

p v = p´ v´ = constant.

Boyle is said to have "discovered" this law, and Harvey is said to have "discovered" the circulation of the blood. Doubtless they did: but if they had done no more than "discover" these things, no one else would have been the wiser, and the world would have been no richer. What these two men did that made us wiser and the world richer, was to make inventions of definite character, and give them to the world in such manageable forms, that "persons skilled in the art can make and use them."

In 1620, the spirit thermometer, as we know it now, was invented by Drebel. It is by some ascribed to Galileo. An interesting controversy has been waged as to which was actually the inventor. The facts seem to be that Galileo did invent a thermometer in which the height of water in a glass tube indicated approximately the temperature. The tube was long and ended in a bulb at the top. The bulb being warmed with the hand of Galileo, and the open lower end of the tube being immersed in water, and then the warmth of the hand removed, water rose in the tube to a height depending on the warmth of the air in the bulb. The height of the water therefore varied inversely as the temperature. The defect of the instrument was that it was a barometer as much as it was a thermometer; because the varying pressure of the atmosphere caused the water to rise and fall accordingly, and thus falsify the thermal indications. Drebel realized this, and closed both ends of the tube.

Thus Galileo came very near to inventing both the thermometer and the barometer, but yet invented neither! It seems incredible that he should have failed to invent the barometer, having come so near it; for he had been engaged for a long period in investigating the weight of air, and finally had succeeded in ascertaining it. The barometer was invented or rather discovered by Galileo's successor, Torricelli, in 1645. Torricelli, in investigating the action of suction pumps, constructed what now we call a barometer; but it was not until after he had constructed it that he realized that the height of mercury in his tube indicated the pressure of the air outside. Seventy-five years later, Fahrenheit made a great improvement in the thermometer by substituting mercury for spirits.

Meanwhile, Otto von Guericke, following in the footsteps of Galileo and Torricelli, had invented the air-pump, by means of which he succeeded in getting a fairly perfect vacuum in a glass receiver. This seems to have been an invention of the most clear-cut kind, resulting from an idea that occurred to Guericke that he seized upon promptly and put to work to serve mankind. Its influence in giving impetus to the science and art of pneumatics, and the influence of pneumatics on the progress of civilization, are too obvious to need more than to be pointed out. The invention of Guericke is a simple and clear illustration of the "power of an idea"; an illustration of seed falling on good ground and bringing forth fruit an hundred fold.

One of the greatest inventors that ever lived was Isaac Newton, who lived from 1642 till 1728. Even as a child he busied himself with contriving and constructing mechanical appliances, mostly toys. As a young man he occupied himself mostly with studies in mathematics and experiments in physics, especially optics. In 1671 he invented a special form of the reflecting telescope, called after him the Newtonian telescope. He made many experiments in optics, in consequence of which he discovered and announced that white light consists of seven colors, having different degrees of refrangibility. The influence of this discovery on the advancement of learning since that time, it is unnecessary to point out; but we cannot realize too clearly that without it much of the most important progress in optics since that time would have been impossible.

The invention by reason of which Newton is most generally known is his theory or law of gravitation, which he announced in his Principia, published in 1686. In 1609, Kepler had announced his famous laws, that reads:

"1. The orbits of planets are ellipses having the sun at one focus.

"2. The area swept over per hour by the radius joining sun and planet is the same in all parts of the planet's orbit.

"3. The squares of the periodic times of the planets are proportional to the cubes of their mean distances from the sun."

Newton showed from the laws of mechanics which he had discovered that, assuming the first two laws of Kepler to be true, each planet must always be subject to a force directing it toward the sun, that varies inversely as the square of its distance from the sun: otherwise, it would fly away from the sun or toward it. From this, Newton inferred that all masses, great and small, attract each other with a force proportional to their masses, and inversely proportional to the square of the distance between them, and invented what is now called the law of universal gravitation.

Another invention of possibly equal value, also published in his Principia, but not so generally known, is his three laws of motion. These are

"1. Every body continues in its state of rest, or of moving with constant velocity in a straight line, unless acted upon by some external force.

"2. Change of momentum is proportional to the force and to the time during which it acts, and is in the same direction as the force.

"3. To every action there is an equal and contrary re-action."

It is probably impossible for any human mind to conceive any invention of a higher order of originality than either of these two, or to construct any invention more concrete and useful. Certainly no more brilliant inventions have ever yet been made. These two wonderful products of Newton's genius underlie the whole structure of modern astronomy and modern mechanics. The sciences of modern astronomy and modern mechanics could not exist without them, and would not now exist unless Newton (or someone else) had invented them.

It may be pointed out that Newton's conception of our solar system is that of a machine in rapid motion, of which the sun and the planets are the principal parts.

Another important invention ascribed to Newton is that of the sextant, a small and easily handled instrument, used ever since in ships for purposes of navigation; but whether he should receive the entire credit for this invention seems quite doubtful; for another astronomer, Robert Hooke, is credited by some with the original suggestion, and John Hadley, still another astronomer, with having adapted it to practical sea use. Numerous other scientific inventions, however, that have formed the basis of much of the scientific work of later experimenters and inventors are clearly to be credited to Newton. Among these, his formula for the velocity of a wave of compression, his color-wheel, and his simple apparatus known as "Newton's rings," by which can be measured the wave lengths of light of different colors, are possibly the most important.

In approximate coincidence with the Renaissance movement and the accompanying awakening of the intellect of Europe, there began a conflict between the sovereigns and the Pope. The Popes had gradually acquired great power, because of their prestige as the successors of St. Peter, to whom it was declared our Savior had given the keys of heaven. Coincidentally, the multitudinous barons had gradually built up the Feudal System. This was a loose-jointed contrivance, under which Europe was virtually divided into little geographical sections, ruled over by hereditary feudal lords, who in each country owed allegiance to a sovereign. By reason of the slowness and uncertainty of transportation and communication, the various feudal lords were extremely independent, and each one did substantially as he willed in his little domain.

The situation was a miserable one for every person, except the Pope, the sovereigns, the feudal lords and their hangers-on; not only because of the various petty tyrannies, but because of the continual little wars and the general absence of good government. Gradually, the sovereigns got more and more power (except in England) and the conditions improved so much that the people realized that it was better to be ruled by one king, or emperor, than by a multitude of barons. The sovereigns finally acquired so much power that they dared to oppose the Pope in many of his aggressions; but no very important situations were developed until the Reformation caused the existence of protestant or heretic sovereigns, and the occasional excommunication of one of them by the Pope, with its attendant exhortation to his subjects to take up arms against him. To meet this situation, the theory of the Divine Right of Kings was invented.

This was a very important invention; for it offset the Divine authority of the Pope as Pope, and gave a theme for the bishops and priests in their discourses to the people, and a slogan for the soldiers. It was extremely successful for three centuries, and its influence was in the main beneficent. It worked for the establishment of stable governments and great nations, tended to prevent the excessive domination of a religious organization, and, by recognizing the fact that every sovereign's power comes from the Almighty, it suggested the sovereign's responsibility to Him. At first this suggestion evidently bore little fruit; for the seventeenth and eighteenth centuries were characterized by general oppression of the people, and filled with dynastic wars, waged merely in behalf of monarchical ambitions. But gradually the kings and the peoples came to realize the duties of sovereigns, as well as their privileges and powers. Gradually then, the view came to be held that kings were bound to exercise their power for the benefit of their people.

Even the doctrine of the Divine Right of Kings, now condemned and obsolete, had a great influence and a good influence during the time it was in vogue; and it supplies a clear illustration of the power of a good idea, skillfully developed, to fulfill a given purpose, so long as its existence is necessary.

Most men have a considerable amount of energy, but do not know what to do with it. Children are in the same category, except that toys have been invented for them, and parents give these toys to their children. Without toys, children find the days very long, and parents find their children very trying. The usefulness of toys seems to be mainly, not so much in giving children pleasure directly, as in supplying an outlet for their energies, both physical and mental. For what greater pleasure is there than in expending one's natural energies under pleasant conditions?

Possibly, all the work that men have done in building up civilization is like the work that children have done with building blocks. Certainly there are many points of similarity. The mental efforts are similar; and, so far as we can see, the results are similar also. Toy temples have been built of building blocks, and then have been destroyed. Civilizations also have been built and then destroyed. And in the case of both the building blocks and the civilizations, the pleasure seems to come, not from the result achieved, but from an enjoyable expenditure of energy in achieving it. In both cases it has been the inventors who have pointed out the ways in which to expend the energy, and achieve the results.