PHYSICAL SCIENCE OF THE CENTURY

While it is universally conceded that the Renaissance was a supremely great period in all the arts and literature, in education and scholarship, and that its geographical discoveries made it noteworthy from another standpoint, there is a very prevalent impression that it was distinctly lacking in scientific development and that indeed the proper attitude of mind for successful scientific investigation was a much later evolution. Most of the discoveries of even basic notions in science are almost universally thought to have been reserved for our time or at least for generations much nearer to us than Columbus’ Century.

Nothing could well be less consonant with the actual history of science than any such impression. At many times before ours man has made great scientific progress. The greatest mystery of human history is that often after great discoveries were made they were somehow lost sight of. Over and over again men forget their previous knowledge and have to begin once more. There was one of these magnificent developments of scientific thought in every department during Columbus’ Century and discoveries were made and conclusions reached which revolutionized other modes of scientific thinking just as much as Columbus’ discovery of America revolutionized geography, or the work of Raphael or Michelangelo and Leonardo revolutionized the artistic thought of the world.

When we recall that it was at this time that Copernicus set forth the theory which has probably more influenced human thinking than any other and that this discovery developed directly from the mathematics of the time and while Vesalius revolutionized anatomy, the discovery of the circulation of the blood began a similar revolution in physiology and the foundations of botany and of modern chemistry in their relations to medicine were laid, some idea of the greatness of the scientific advance of this period will be realized. Mathematics, particularly, developed marvellously and it is always when new horizons are opening out in mathematics that the exact sciences are sure to have a period of wonderful progress. Beautiful hospitals were erected and whenever there are good hospitals, surgery makes progress and that care for the patient which constitutes the essential part of medicine at all times, receives careful attention.

Above all the men of the Renaissance took it on themselves to edit and translate and publish the ancient classics of science and make them available for the study of their own and subsequent generations. The debt which the modern world owes to the Renaissance in this matter is only coming to be properly realized as a consequence of our own development of scholarship in this generation. Only the profound scholar is likely to appreciate properly how much we are indebted to the patient, time-taking work of this period in making books available. Not only the ancient classics but also the works of the Middle Ages on scientific subjects were all published. The early Christian scholars, the Arabians, and above all, the great teachers of the later Middle Ages were edited and printed as an enduring heritage for mankind.

The index of the feeling of the time toward physical science as well as the interest of the scholars of the period in nearly every phase of it is illustrated by the life of Cardinal Nicholas of Cusa, who is usually known as Cusanus. He was a distinguished German churchman who was made Bishop of Brixen and afterwards Cardinal and who had the confidence of the Popes to such a degree that he was sent out as Legate for the correction of abuses in Germany. He was particularly interested in mathematics and the great German historian of mathematics. Cantor, devotes a score of pages to the advances in mathematics which we owe to Cusanus. According to tradition during his journeys over the rough roads in the rude carriage of the time, he studied the curve described through the air by a fly as it was carried round the wheel after alighting on the top of it. He recognized this as a particular kind of curve which we know now as the cycloid and he studied many of its peculiarities and suggested its mathematical import.

He was particularly interested in astronomy and declared that the earth was round, was not the centre of the universe and that it could not be absolutely at rest. As he put it in Latin: terra igitur, quae centrum esse nequit, motu omni carere non potest. He described very clearly how the earth moved around its own axis, and then he added what cannot but seem a surprising declaration for those who in our time think such an idea of much later origin, that he considered that the earth itself cannot be fixed, but moves as do the other stars in the heavens, Consideravi quod terra ista non potest esse fixa sed movetur ut aliae stellae. More surprising still, he even seems to have reached by anticipation some idea of the constitution of the sun. He said: “To a spectator on the surface of the sun the splendor which appears to us would be invisible since it contains as it were an earth for its central mass with a circumferential envelope of light and heat and between the two an atmosphere of water and clouds and of ambient air.”

These expressions occur mainly in a book "De Docta Ignorantia," in which the Cardinal points out how many things which even educated people think they know are quite wrong. His other books are on mathematics, though there is a little treatise on the correction of the calendar which shows how thoroughly the men of the time recognized the error that had crept into the year and how capable they were of making the correction. In a book of his on “Static Experiments” he has a very original discussion of laboratory methods for the study of disease which is eminently scientific, and which is described in the chapter on Medicine.

The life of George von Peuerbach, also Puerbach and Purbachius, the Austrian astronomer, one of Cardinal Nicholas’ proteges who lived to be scarcely forty and whose greatest work was done just at the beginning of Columbus’ Century, is an excellent index of the scientific spirit of the time. About 1440, when he was not yet twenty years of age, he received the degree of Master of Philosophy and of the Liberal Arts with the highest honors at the University of Vienna. After this he seemed to have spent some time at postgraduate work in Vienna, especially in mathematics under Johann von Gmuenden. Just about the beginning of Columbus’ Century he went to Italy. Cardinal Nicholas of Cusa became interested in him and secured him a lectureship on Astronomy at the University of Ferrara. During the next few years he refused offers of professorships, at Bologna and Padua, because he wanted to go back to Vienna to teach in his alma mater. There, with the true Renaissance spirit of non-specialism, he lectured on philology and classical literature, giving special postgraduate courses in mathematics and astronomy. It was at this time that Johann Mueller, Regiomontanus, as he is known, came under his tutelage. Purbach deserves the name that has been given him of the father of mathematical astronomy in modern times.

He introduced the decimal system to replace the cumbersome duodecimal method of calculation, which up to his time had been used in mathematical astronomy. He took up the translation of Ptolemy’s “Almagest,” replaced chords by sines and calculated tables of sines for every minute of arc for a radius of 600,000 units. This wonderful work of simplification naturally attracted wide attention. Cardinal Bessarion was brought in touch with him during a visit to Vienna and was impressed with his genius as an observer and a teacher. He suggested that the work on Ptolemy should not be done on the faulty Latin translation which was the only one available in Vienna at the moment, but on some of the Greek manuscripts of the great Alexandrian astronomer. He offered to secure them and also to provide for Purbach’s support during the stay in Rome necessary for the study. The invitation was accepted on condition that his pupil Regiomontanus should go with him. Unfortunately, however, Purbach died before his journey to Rome. His works were very popular in his own time and his commentary on the “Almagest of Ptolemy” as completed by Regiomontanus became one of the standard text-books of the time. Altogether there are some twenty of his works extant and his “New Theory of the Planets” remained a favorite book of reference for astronomers even long after the publication of Copernicus. His industry must have been enormous but was after all not different from that of many of his contemporaries.

Astronomy was to be the great stimulating physical science of the early part of Columbus’ Century and Purbach’s successor in the chain of scientific genius at this time was his pupil Johann Mueller, or as he has come to be known from the Latinization of the name of the place of his birth, Koenigsberg (in Franconia, not far from Munich), Regiomontanus. As we have said, young Mueller made his studies with Purbach at Vienna, became very much interested in astronomy and mathematics, at his master’s suggestion accompanied Cardinal Bessarion to Italy and under his patronage took up the work of providing an abridgment of Ptolemy’s great work, the “Almagest,” in a Latin translation for those who might be deterred from the Greek.

Cardinal Bessarion became very much interested in him and gave him a chance to study in Italy. Mueller chose Padua and spent nearly ten years there. Whenever anybody in almost any country in Europe wanted to secure opportunities for study beyond those afforded by his native land at this time he went down to Padua. Linacre, Vesalius, John Caius went there for medicine, Copernicus, a little later than Regiomontanus, for mathematics and astronomy and it was the ardently desired goal of many a student’s wishes. Mueller spent nearly ten years in Italy, most of it at Padua and at the age of about thirty-five returned to Germany to take up his life work. He settled down in Nuremberg, where in connection with Bernard Walther he secured the erection of an observatory. Nuremberg, because of its fine work in the metals, was the best place to obtain mechanical contrivances of all kinds, and many of these were used for the first time for scientific purposes at this observatory. It became quite a show place for visitors and while Nuremberg was developing the literary and artistic circles in which the Pirkheimers, Albrecht Duerer and the Vischers and Adam Kraft shone conspicuously, scientific interest in the city was at a similar high level.

Mueller made a series of observations of great value in the astronomy of the time and substituted Venus for the moon as a connecting link between observations of the sun, the stars and the earth. He recognized the influence of refraction in altering the apparent places of the stars and he introduced the use of the tangent in mathematics. His most important work for the time, however, was the publication of a series of astronomical leaflets, "Ephemerides Astronomicae" in which his observations were published and also a series of calendars for popular information. These announced the eclipses, solar and lunar, for years before their recurrence and gave a high standing to astronomy as a science. Some of these leaflets even reached Spain and Portugal and encouraged Spanish and Portuguese navigators with the thought that they could depend on observations of the stars for their guidance at sea. In a way, then, Regiomontanus’ work prepared the path along which Columbus’ discovery was made.

Regiomontanus’ work attracted so much attention that he was invited to Rome to become the Papal Astronomer and to take up the practical work of correcting the Calendar. Unfortunately he died not long after his arrival in Rome, though not before he had been chosen as Bishop of Regensberg (Ratisbon) as a tribute to his scholarship and his piety. He thus became a successor of Albertus Magnus (in the bishopric), who had been in his time one of the profoundest of scholars and greatest of scientists. The tradition of appreciation of scholarship and original research had evidently been maintained for the three centuries that separate the two bishop scientists.

A distinguished scientific student born at Nuremberg the same year as Regiomontanus was Martin Behem or Behaim, the well-known navigator and cartographer, who on his return to Nuremberg in 1493 made the famous terrestrial globe which was meant to illustrate for his townsmen the present state of geography as the Spaniards and Portuguese had been remaking it. Behem’s work is a striking testimony to the excellence of geographic knowledge at this time, and only for the preservation of this globe we could scarcely have believed in the modern time how correct were the notions of the scholars of the period with regard to the older continent at least.

One of the great physical scientists of this time is Toscanelli, the physician, mathematician, astronomer and cosmographer, over whose connection with Columbus such a controversy has raged in recent years. He and Cardinal Cusanus were fellow students at the University of Padua, where Toscanelli’s course consisted of mathematics, philosophy and medicine. He settled down as a practising physician in Florence and took up scientific studies of many kinds which brought him into connection not only with the students of science, but with the scholars and artists of the time. Brunelleschi and he were intimate friends, but he was well known outside of Italy, and Regiomontanus often consulted him. His services to astronomy consist in the painstaking and exact observations on the orbit of the comets of 1433, 1449-50 and especially of Halley’s comet on its appearance in 1456 and of the comets of May, 1457, June, July and August of the same year. These show a most accurate power of astronomical observation and profound mathematical knowledge for that time. His famous chart indicated just how a navigator might reach the coast of India by sailing westward, and Columbus is said to have carried a copy of this chart with him on his first voyage. Whether this is true or not, there is no doubt of Toscanelli’s place in the history of science because of original work in astronomy, geodesy and geography.

The most important protagonist of physical science during Columbus’ Century, however, was undoubtedly Copernicus. Columbus gave the men of his time a new world, but Copernicus gave them a new creation. When early in the sixteenth century he published a preliminary sketch of his theory, one of his ecclesiastical friends remarked to him that he was giving his generation a new universe. There has probably never been a theory advanced which has changed men’s modes of thinking with regard to the world they live in and their relation to it as the Copernican hypothesis has done, though it must not be forgotten that there are some as yet insuperable difficulties which keep it still in the class of scientific hypotheses.

The earth had up to this time been universally thought of as the centre of the universe, much more important than any of the other bodies, sun, moon or stars, and all the others were thought to move around it. Their apparent movement was due to the rotation of the earth, which was quite unrecognized. The immense distances of space were entirely undreamt of. In the new order of thinking the earth became a minor planet of small size in our solar system which was of inconspicuous magnitude when compared to the totality of the other bodies of the universe. The acceptance of the new theory sank man in his own estimation very considerably. The change of point of view of the meaning of the universe necessitated by the Copernican theory was ever so much greater than that demanded by evolution in our time.

It took two centuries for men to adjust their thinking to these new ideas. Francis Bacon, a full century after Copernicus’ time, declared emphatically that the Copernican theory did not explain the known facts of astronomy as well as the Ptolemaic theory. In Bacon’s time Galileo was the subject of persecution and the reason for the persecution was that he was advancing a doctrine which no other great astronomer of his time accepted, and advancing it for reasons which have not held in the after-time. The Copernican theory came eventually to be accepted for quite different reasons from those advanced by Galileo.

How Copernicus succeeded in coming to this magnificent generalization is indeed hard to understand. It is easier to get some notion of it, however, when his achievement is taken in connection with what was being done all around him at this time. Living in a century when great men were accomplishing triumphs in painting, sculpture, architecture that have been the wonder of the world ever since, and when geography was being revolutionized, and nearly every science awakened, it is not surprising that he should have reached a height of mathematical and astronomical expression beyond any that men had ever conceived before and that he should have surpassed many of the generations to come after him, by the clearness of his intuition of the astronomical mystery of the universe.

Copernicus had not made many observations nor were such observations as had been made by him worked out with that painstaking accuracy which might be thought necessary to reach a great new conception of the universe. He had the genius to see from even the few and imperfect data that he had at hand what the true explanation of the diverse phenomena of the heavens was. He had no demonstrations to advance. He argued merely from analogy. Even Galileo, a century later, admitted to Cardinal Bellarmine that he had no strict demonstration of his views to offer, but that “the system seems to be true.” While the feeling of many scientists in the modern time is that great discoveries come from patient accumulation of accurate observations in large numbers, the history of science shows that almost invariably the epochal steps in progress have come from men who were comparatively young as a rule and who were not overloaded with the information of their time. The great artists of the Renaissance could probably have given no better reasons for their artistic conceptions than Copernicus for his stroke of genius, but they were all working at a time when somehow men were capable as they never have been since of these far-reaching intellectual achievements.

Copernicus was a Pole who, like other students of his time, gladly welcomed the opportunity to go down to Italy for post-graduate work, studied with Novara at Padua mathematics and astronomy and was quite willing to add the study of medicine, because by so doing he could secure an extension of the length of time he would be allowed to remain in Italy. He then returned to be a canon of the Cathedral of Frauenberg, and spent forty years in quiet patient observation and in the practice of his medical profession not for money, but for the benefit of the poor and such friends of the chapter of the Cathedral as he was under obligations to because of the years they had supported him in Italy. He probably reached his great astronomical theory when he was about thirty. He did not publish the preliminary sketch of it for twenty-five years. He did not publish his great book until just before his death, keeping it by him, making changes in it and while thoroughly convinced of its importance, quite sure that, owing to its lack of definite demonstration, it would not be generally accepted.

Like so many of these geniuses of the Renaissance he was a simple kindly man who had many good friends among those around him and who had one of the very happy lives accorded to those who, having some great thought and great work to occupy themselves with, have daily duties that afford them diversion and bring them into contact with friends in many ordinary relations in life. His humility of heart and simplicity of character, as well as his deep religious faith, can be very well appreciated from the prayer which at his own request was the only inscription upon his tombstone: “I ask not the grace accorded to Paul, not that given to Peter; give me only the favor Thou didst show to the thief on the Cross.”

His attitude toward the reform movement, twenty years of which he lived through in Germany, is interesting. He was an intimate friend of Bishop Maurice Ferber of Ermland, who kept his see loyal to Rome at an epoch when the secularization of the Teutonic Order and the falling away of many bishops all around him make his position and that of his diocese noteworthy in the history of that place and time. Copernicus continued loyal to the old Church and in 1541 his great book "De Revolutionibus Orbium Celestium" was dedicated to Pope Paul III, who accepted the dedication and until the Galileo matter brought Copemicanism prominently into question there was never any thought of Copernicus’ book as containing matters opposed to faith. It was then placed on the Index, but only until some minor passages should be corrected which set forth the new theory as if it were an astronomical doctrine founded on facts and demonstrations and not a hypothesis still to be discussed by scientists.

The scientific spirit of this century is often scouted because in spite of their scientific knowledge many of the astronomers and mathematicians of this time as well as, of course, other educated men following their example, could not quite rid themselves of the idea that the stars were powerful influences over man’s life and health. The history of this idea, however, minimizes the objection. All down the centuries men like Roger Bacon, Albertus Magnus, Nicholas of Cusa, Marsilio Ficino and Pico della Mirandola insisted that there could be nothing in what we now call astrology. Men parted with the older ideas very slowly, however. Almost a hundred years after Columbus’ Century even Galileo made horoscopes and seems to have thoroughly believed in them, though some of his prophecies were sadly mistaken. Kepler drew up horoscopes, confessing that he had not much confidence in them but that they were paid for much better than other mathematical work and he sadly needed the money. Lord Bacon could not quite persuade himself that there was nothing in astrology. As late as after the middle of the eighteenth century Mesmer’s thesis for graduation in medicine at the University of Vienna, which at that time had one of the best medical schools of Europe, was on the influence of the stars on human constitutions. It was accepted by the faculty and he got his degree. Even in our time, though now the educated contemn, the mass of the people still have not entirely rejected astrology. The men of Columbus’ Century can scarcely be thought less of for having accepted it, though many of the scientists of the time did not.

The counterpart to the great scientific genius that Copernicus was, the generalizer who discloses a new horizon, was to be found in his contemporary, Leonardo da Vinci, who was an inventor, a practical genius applying discoveries to everyday life. He solved most of the mechanical problems, invented locks for canals, the wheelbarrow and special methods of excavation, a machine for making files by machinery, run by a weight, a machine for sawing marble blocks instead of separating them by natural cleavage, the model of those still employed at Carrara, as well as machines for planing iron, for making vices, saws and planes, for spinning, for shearing the nap of cloth, as well as an artist’s sketching stool, a color grinder, a spring to keep doors shut, a roasting jack, a hood for chimneys, movable derricks quite similar to those in use among us to-day, with contrivances for setting up marble columns on their bases, one of which in principle was used to set up Cleopatra’s Needle on the Embankment in London in our time. A favorite field of invention was that of all sorts of apparatus relating to war, military engines, devices for pushing scaling ladders away from walls and many others. He was probably the greatest inventive genius in the world’s history. He had an eminently practical mind. He devoted himself to the problem of flying, studied the wings of birds and produced a series of mechanical devices, tending toward the solution of that problem.

Taine said of him: “Leonardo da Vinci is the inventor by anticipation of all the modern ideas and of all the modern curiosities, a universal and refined genius, a solitary and inappeasable investigator, pushing his divinations beyond his century so as at some times to reach ours.” There was scarcely anything that he touched that he did not illuminate wonderfully by his genius. In studying the muscles of animals he invented a dynamometer, he improved spectacles and studied the laws of light, invented the camera obscura and in his steam experiments anticipated Watt. A very curious feature of his work is his series of experiments with the steam gun, with which he was sure that great destruction might be worked.

A very interesting invention of a scientific instrument of some precision by Leonardo was what may be called a weather gauge. This was made of a copper ring with a small rod of wood, which acted as a balance. On it were two little balls, one covered with wax and the other with material that absorbed moisture readily. When the air was saturated with moisture this ball grew heavy and inclined the beam till it touched one of the divisions marked on the copper ring set behind it. The degree of moisture could thus be seen and the weather, or at least changes in it, could be predicted. We have a whole series of such arrangements mainly in the shape of toys in the modern time. The hygroscopic qualities of cord or the tendency of certain colors to change their tints when more moisture is present are used to indicate approaching changes in the weather. Leonardo seems to have been the first to make use of this practically and he deserves the credit of priority in the invention.

His studies in optics might almost naturally be expected from a painter so much occupied with color and whose intense curiosity prompted him to know not merely the use of things but the causes of and the reasons for them. He evolved much of the science of color vision, suggested the principles of optics that came to be known only much later, analyzed and explained the construction of the eye, invented the camera obscura in imitation of it and gave us a theory of color vision which is as good as any other that we have down to the present day. These optical studies alone might well be considered as enough to occupy an ordinary lifetime, but they seem to have been only the results of a series of interludes of the nature of recreation for Leonardo. He made his notes on the subject, filed them away with others, made no attempt to print his conclusions, probably found very few with whom he could discuss the subject, but he had satisfied himself. That was what he wanted.

After knowing such facts as this we are not surprised to learn of his anticipating by some sort of divination the laws of gravitation, the molecular composition of water, the motion of waves, the undulatory theory of light and heat, the earth’s rotation and rotundity before Columbus’ time and many other surprising things. One finds in his diary that he was planning the construction of a harbor and studying the music of the waves on the beach at the same time.

Poggendorff, in his great Biographical Dictionary of prominent men of science, quotes Libri’s “History of Mathematics in Italy” as authority for the declaration that Leonardo discovered capillarity and diffraction, made use of the signs + and -, knew the camera obscura (without a lens), made observations on resistance, on density, on the weight of the air, on dust figures, on vibrating surfaces and on friction and its effects.

All sorts of machines came from Leonardo’s hands. He had a positive genius for practical invention that has probably never been equalled, surely not surpassed, even down to our own day. His inventive faculty worked itself out, in machines of such variety as have never come from the brain of a single individual before. Nor were these merely primitive mechanical devices that we would surely despise now. On the contrary, nearly all of them have endured in principle at least and some of them almost as they came from him.

Leonardo also did distinguished work in the biological sciences, so that Duval, Professor of Anatomy at the University of Paris and himself well known both for his researches in biology and his knowledge of the history of science, entitles an article with regard to him in the French Revue Scientifique (De, 1889), “A Biologist of the Fifteenth Century.” His biological discoveries are discussed in the chapter on the Biological Sciences.

Sometimes it is asserted by those who are so little familiar with the history of science that they venture on such assertions rather easily, that the true scientific spirit had not yet awakened and that while men were making many observations and acquiring new information they had not as yet the proper scientific attitude of mind to make really great discoveries. It is rather amusing to be told that of a century when Copernicus and Vesalius and so many other distinguished modern scientists were alive. Some writers suggest that the true rising of the modern spirit of scientific inquiry did not come until Francis Bacon’s time. Francis Bacon is one of the idols of the marketplace, but surely no serious student of history accords him the place in science that our English forbears gave him when they were insular enough to know very little about continental work, and above all about Italian workers.

Francis Bacon, of course, had been long anticipated in all that concerns the inductive method in science by his much greater namesake Roger Bacon. In Columbus’ Century however, a hundred years before Bacon’s time, Bernardino Telesio, the Italian philosopher, stated fully the inductive method and recognized all its possibilities. In Science for December 19, 1913, Professor Carmichael said of him:

“He abandoned completely the purely intellectual sphere of the ancient Greeks and other thinkers prior to his time and proposed an inquiry into the data given by the senses. He held that from these data all true knowledge really comes. The work of Telesio, therefore, marks the fundamental revolution in scientific thought by which we pass over from the ancient to the modern methods. He was successful in showing that from Aristotle the appeal lay to nature, and he made possible the day when men would no longer treat the ipse dixit of the Stagirite philosopher as the final authority in matters of science.”

The tendency of this century to make scientific principles of value for practical purposes is well illustrated by the references to the sympathetic telegraph which began to be much talked of at this time. According to the story as told, friends at a distance might be able to communicate with each other by having two dials around which the letters of the alphabet were arranged with a magnetic needle swinging free as the indicator. When the needle on one of the dials was moved to a letter, the other by magnetic attraction was supposed to turn to the same letter. This ingenious conceit has been attributed to Cardinal Bembo, one of the great scholars of the Renaissance, who was private secretary to Pope Leo X. His friend Porta, the versatile philosopher, made it widely known by the vivid description which he gave of it in his celebrated work on “Natural Magic,” published just after the close of Columbus’ Century.

A very important development in science came in the application of chemistry to medicine, both as regards physiology and pathology. Basil Valentine at the beginning of Columbus’ Century led the way and Paracelsus did much to indicate what the advantage of the application of chemistry to medicine would be. Paracelsus compared the processes in the human body with chemical phenomena and declared that alterations in the chemical conditions of organs were the causes of disease. He set himself up in opposition to the humoral theory of the ancients and denied that the heart was the seat of heat manufacture in the body, for every portion of the system had, he asserted, its source of heat. It was through Paracelsus that chemistry was added to the medical curriculum and George Korn in his chapter on Medical Chemistry in Puschmann’s “Handbook” attributes the foundation of certain professorships for chemistry at the universities of this time to Paracelsus’ influence. Andreas Libavius did much to advance chemical science in various directions by his study and preparation of sulphuric acid and his recognition of the identity of the substance made from sulphur and saltpeter with that obtained from vitriol and alum. Studies of this kind brought a broad realization of the possibilities of chemistry.

The spirit of the period as regards science and the development of the faculty of observation at this time is very well illustrated by Columbus’ own observations on the declination of the magnetic needle during his first voyage across the ocean. Brother Potamian has told the story in Makers of Electricity :

“It is one of the gems in the crown of Columbus, that he observed, measured and recorded this strange behavior of the magnetic needle in his narrative of the voyage. True, he did not notice it until he was far out on the trackless ocean. A week had elapsed since he left the lordly Teneriffe, and a few days since the mountainous outline of Gomera had disappeared from sight. The memorable night was that of September 13th, 1492. There was no mistaking it; the needle of the Santa Maria pointed a little west of north instead of due north. Some days later on September 17th, the pilots, having taken the sun’s amplitude, reported that the variation had reached a whole point of the compass, the alarming amount of 11 degrees.

“The surprise and anxiety which Columbus manifested on those occasions may be taken as indications that the phenomenon was new to him. As a matter of fact, however, his needles were not true even at the outset of the voyage from the port of Palos, where, though no one was aware of it, they pointed about 3 deg. east of north. This angle diminished from day to day as the Admiral kept the prow of his caravel directed to the West, until it vanished altogether, after which the needles veered to the West, and kept moving westward for a time as the flagship proceeded on her voyage.

“Columbus thus determined a place on the Atlantic in which the magnetic meridian coincided with the geographical and in which the needle stood true to the pole. Six years later, in 1498, Sebastian Cabot found another place on the same ocean, a little further north, in which the compass lay exactly in the north-and-south line. These two observations, one by Columbus and the other by Cabot, sufficed to determine the position of the agonic line, or line of no variation, for that locality and epoch.

“The Columbian line acquired at once considerable importance in the geographical and the political world, because of the proposal that was made to discard the Island of Ferro and take it for the prime meridian from which longitude would be reckoned east and west, and also because it was selected by Pope Alexander VI to serve as a line of reference in settling the rival claims of the kingdoms of Portugal and Castile with regard to their respective discoveries. It was decided that all recently discovered lands lying to the east of that line should belong to Portugal; and those of the west to Castile.”

The first observation of magnetic declination on land appears to have been made about the year 1510 by George Hartmann, Vicar of the Church of St. Sebald, Nuremberg, who found it to be 6 deg. East in Rome, where he was living at the time. He observed it also in Nuremberg, where the needle pointed ten degrees East of North. Columbus’ explanation of the declination to his sailors is interesting. He kept silence about it at first, but when they grew alarmed, believing that the laws of nature were changing as they advanced farther and farther into the unknown, he told them that the needle did not point to the North Star, which had been called the Cynosure, but to a fixed point in the celestial sphere and that Polaris itself was not stationary, but had a rotational movement of its own, like all other heavenly bodies. They trusted him and their fears were allayed and a mutiny averted. When on his return to Spain he reported the many and definite observations on the variation of the compass which he had made he was told by the scientists of the time that he, and not the needle, was in error, because the latter was everywhere true to the pole. Just why they were sure it was so they could not tell, but they refused to believe even observations which showed that it was not so; though these were reported by a man who had just overturned quite as strong convictions by sailing westward and reaching land. It is such contradictions of what seem to be obviously first principles of science that in all ages have constituted great discoveries and required genius to make them.