The ancients laid down the laws of literary form in prose as well as in verse, and bequeathed to posterity works which still serve as models of excellence. Their poets and historians continue to be read for the sake of the narrative and beauty of the style; their philosophers for breadth and depth of thought; and their orators for judicious analysis and impassioned eloquence.

In the exact sciences, too, the ancients were conspicuous leaders by reason of the number and magnitude of the discoveries which they made. You have only to think of Euclid and his "Elements," of Apollonius and his Conics, of Eratosthenes and his determination of the earth's circumference, of Archimedes and his mensuration of the sphere, and of the inscription on Plato's Academy, Let none ignorant of geometry enter my door, to realize the fondness of the Greek mind for abstract truth and its suppleness and ingenuity in mathematical investigation.

But the sciences of observation did not advance with equal pace; nor was this to be expected, as time is an essential element in experimentation and in the collection of data, both of which are necessary for the framing of theories in explanation of natural phenomena.The slowness of advance is well seen in the development of the twin subjects of electricity and magnetism. As to the lodestone, with which we are concerned at present, the attractive property was the only one known to ancient philosophy for a period of six hundred years, from the time of Thales to the age of the CÆsars, when Lucretius wrote on the nature of things in Latin verse.

Lucretius records the scant magnetic knowledge of his predecessors and then proceeds to unfold a theory of his own to account for the phenomena of the wonder-working stone. Book VI. of "De Natura Rerum" contains his speculations anent the magnet, together with certain observations which show that the poet was not only a thinker, but somewhat of an experimenter as well. Thus he recognizes magnetic repulsion when he says: "It happens, too, at times that the substance of the iron recedes from the stone as if accustomed to start back from it, and by turns to follow it."

This recognition of the repelling property of the lodestone is immediately followed by the description of an experiment which is frequently referred to in works on magnetic philosophy. It reads: "Thus have I seen raspings of iron, lying in brazen vessels, thrown into agitation and start up when the magnet was moved beneath"; or metrically,

This experiment, seen and recorded by Lucretius, is of special interest to the student of magnetic history because of the use which is made of iron filings and also because it has led certain writers to credit the poet with a knowledge of what is known to-day by the various names of magnetic figures, magnetic curves, magnetic spectrum. We do not, however, share this view, because we see no adequate resemblance between the positions assumed by the bristling particles of iron in the one case, as described by the Roman poet, and the continuous symmetrical curves of our laboratories in the other. If Lucretius noticed such curves in his brazen vessels, he does not say so; nor does the meagre description of magnetic phenomena given in Book VI. warrant us in assuming that he did.

The use of iron filings to map out the entire field of force that surrounds a magnet was unknown to classical antiquity; it was not known to Peregrinus or Roger Bacon in the thirteenth century or even to Gilbert in the sixteenth. The credit for reviving the use of filings and employing them to show the direction of the resultant force at any point in the neighborhood of a magnet, belongs to Cabeo, an Italian Jesuit, who described and illustrated it in his "Philosophia Magnetica," published at Ferrara in the year 1629. On page 316 of that celebrated work will be found a figure, the first of the kind, showing the position taken by the filings when plentifully sifted over a lodestone: thick tufts at the polar ends with curved lines in the other parts of the field.

The Samothracian rings mentioned in the passage quoted above were light, hollow rings of iron which, for the amusement of the crowd, the jugglers of the times held suspended one from the other by the power of a lodestone. Writing of the lodestone, Lucretius says:

Though the Roman poet was acquainted with two of the leading properties of the lodestone, viz., attraction and repulsion, there is nothing in the lines quoted above or in any other lines of his great didactic poem to indicate that he was aware of the remarkable difference which there is between one end of a lodestone and the other. The polarity of the magnet, as we term it, was unknown to him and remained unknown for a period of 1200 years.

During that long period nothing of importance was added to the magnetic lore of the world. True, a few fables were dug out of the tomes of ancient writers which gained credence and popularity, partly by reason of the fondness of the human mind for the marvelous, and partly also by reason of the reputation of the authors who stood sponsors for them.

Pliny (23-79 A. D.) devotes several pages of his "Natural History" to the nature and geographical distribution of various kinds of lodestones, one of which was said to repel iron just as the normal lodestone attracts it. Needless to say that the mineral kingdom does not hold such a stone, although Pliny calls it theamedes and says that it was found in Ethiopia. Pliny is responsible for another myth which found favor with subsequent writers for a long time, when he says that a certain architect intended to place a mass of magnetite in the vault of an Alexandrian temple for the purpose of holding an iron statue of Queen Arsinoe suspended in mid-air. Of like fabulous character is the oft-repeated story about Mahomet, that an iron sarcophagus containing his remains was suspended by means of the lodestone between the roof of the temple at Mecca and the ground.

As a matter of fact, Mahomet died at Medina and was buried there in the ordinary manner, so that the story as currently told of the suspension of his coffin in the "Holy City" of Mecca, contains a twofold error, one of place and the other of position. By a recent (1908) imperial irade of the Sultan of Turkey, the tomb is lit up by electric light in a manner that is considered worthy of the "Prophet of Islam."

Four centuries after Pliny, Claudian, the last of the Latin poets as he is styled, wrote an idyl of fifty-seven lines on the magnet, which contains nothing but poetic generalities. St. Ambrose (340-397) and Palladius (368-430), writing on the Brahmans of India, tell how certain magnetic mountains were said to draw iron nails from passing ships and how wooden pegs were substituted for nails in vessels going to Taprobane, the modern Ceylon. St. Augustine (354-430) records in his "De Civitate Dei" the wonder which he felt in seeing scraps of iron contained in a silver dish follow every movement of a lodestone held underneath. With time, the legendary literature of the magnet became abundant and in some respects amusing. Thus we read of the "flesh" magnet endowed with the extraordinary power of adhering to the skin and even of drawing the heart out of a man; the "gold" magnet which would attract particles of the precious metal from an admixture of sand; the "white" magnet used as a philter; magnetic unguents of various kinds, one of which, when smeared over a bald head, would make the hair grow; magnetic plasters for the relief of headache; magnetic applications to ease toothaches and dispel melancholy; magnetic nostrums to cure the dropsy, to quell disputes and even reconcile husband and wife. No less fictitious was the pernicious effect on the lodestone attributed in the early days of the mariner's compass to onions and garlic; and yet, so deeply rooted was the belief in this figment that sailors, while steering by the compass, were forbidden the use of these vegetables lest by their breath they might intoxicate the "index of the pole" and turn it away from its true pointing. More reasonable than this prohibition was the maritime legislation of certain northern countries for the protection of the lodestone on shipboard. According to this penal code, a sailor found guilty of tampering with the lodestone used for stroking the needles, was to have the guilty hand held to a mast of the ship by a dagger thrust through it until, by tearing the flesh away, he wrenched himself free.

It was only at the time of the Crusades that people in Europe began to recognize the directive property of the magnet, in virtue of which a freely suspended compass-needle takes up a definite position relatively to the north-and-south line, property which is serviceable to the traveler on land and supremely useful to the navigator on sea. It is commonly said that the compass was introduced into Europe by the returning Crusaders, who heard of it from their Mussulman foes. These, in turn, derived their knowledge from the Chinese, who are credited with its use on sea as far back as the third century of our era.[1]

Among the earliest references to the sailing compass is that of the trouvÈre Guyot de Provins,[2] who wrote, about the year 1208, a satirical poem of three thousand lines, in which the following passage occurs:

The author was a caustic and fearless critic, who lashed with equal freedom the clergy and laity, nobles and princes, and even the reigning pontiff himself, all of whom should be for their subjects, according to the satirist, what the pole-star is for mariners—a beacon to guide them over the stormy sea of life. Guyot traveled extensively in his early years, but later in life retired from a world which he despised, and ended his days in the peaceful seclusion of the Benedictine Abbey of Cluny.

An interesting reference, of a similar nature to that of the minstrel Guyot, is found in the Spanish code of laws known as Las Siete Partidas of Alfonso el Sabio, begun in 1250 and completed in 1257. It says:

"And even as mariners guide themselves in the dark night by the needle, which is their connecting medium between the lodestone and the star, and thus shows them where they go alike in bad seasons as in good; so those who are to give counsel to the king ought always to guide themselves by justice, which is the connecting medium between God and the world, at all times to give their guerdon to the good and their punishment to the Wicked, to each according to his deserts."[3]

It will be necessary to give a few more extracts from writers of the first half of the thirteenth century in order to show how little was known about the magnet and how crude were the early appliances used in navigation when Peregrinus appeared on the scene.

Cardinal Jacques de Vitry, who lived in the East for some years, wrote his "History of the Orient" between the years 1215 and 1220, in which he says:

"An iron needle after touching the lodestone, turns towards the north star, so that such a needle is necessary for those who navigate the seas."

This passage of the celebrated Cardinal seems to indicate that even then the compass was widely known and commonly used in navigation.

Neckam (1157-1217), the Augustinian Abbot of Cirencester, wrote in his "Utensilibus": "Among the stores of a ship, there must be a needle mounted on a dart which will oscillate and turn until the point looks to the north; the sailors will thus know how to direct their course when the pole-star is concealed through the troubled state of the atmosphere."

This passage is of historical value, as it contains what is probably the earliest known reference to a mounted or pivoted compass. Prior to the introduction of this mode of suspension, the needle was floated on a straw, in a reed, on a piece of cork or a strip of wood, all of which modes of flotation, when taken in conjunction with the unsteadiness of the vessel in troubled waters, must have made observation difficult and unsatisfactory.

Brunetto Latini (1230-1294) makes a passing reference to the new magnetic knowledge in his "Livres dou Tresor," which he wrote in 1260, during his exile in Paris.

"The sailors navigate the seas," he says, "guided by the two stars called tramontanes; and each of the two parts of the lodestone directs the end of the needle that has touched it to the particular star to which that part of the stone itself turns."

Though a statesman, orator and philosopher of ability, the preceptor of Dante in Florence and guest of Friar Bacon in Oxford, Brunetto has not got the philosophy of the needle quite right in this passage; for the part that has been touched by the north end of a lodestone will acquire south polarity and will not, therefore, turn towards the same "tramontane" as the end of the stone by which it was touched.

Dante himself admitted the occult influence on the compass-needle that emanates from the pole-star when he wrote:

The next writer on the compass is Raymond Lully (1236-1315), who was noted for his versatility, voluminous writings and extensive travels as well as for the zeal which he displayed in converting the African Moors. Lully writes in his "De Contemplatione": "As the needle after touching the lodestone, turns to the north, so the mariners' needle directs them over the sea."

This brings us to the last of our ante-Peregrinian writers who make definite allusions to the use of the compass for navigation purposes, viz., Roger Bacon, one of the glories of the thirteenth century as he would be of the twentieth. It was at the request of his patron, Pope Clement IV., that Bacon wrote his "Opus Majus," a work in which he treats of all the sciences and in which he advocates the experimental method as the right one for the study of natural phenomena and the only one that will serve to extend the boundaries of human knowledge. In a section on the magnet, a clear distinction is drawn between the physical properties of the two ends of a lodestone; for "iron which has been touched by a lodestone," he says, "follows the end by which it has been touched and turns away from the other." Besides being a recognition of magnetic polarity, this is equivalent to saying that unlike poles attract while like poles repel each other. Bacon further remarks, by way of corroboration, that if a strip of iron be floated in a basin, the end that was touched by the lodestone will follow the stone, while the other end will flee from it as a lamb from the wolf. There is, however, an earlier recognition known of the polarity of the lodestone; for Abbot Neckam, fifty years before, called attention to the dual nature of the physical action of the lodestone, attracting in one part (say) by sympathy and repelling at the other by antipathy. It was the common belief in Bacon's time and for centuries after, that the compass-needle was directed by the pole-star, often called the sailor's star; but Bacon himself did not think so, preferring to believe with Peregrinus, that it was controlled not by any one star or by any one constellation, but by the entire celestial sphere. Other contemporaries of his sought the cause of the directive property not in the heavens at all, but in the earth itself, attributing it to hypothetical mines of iron which, naturally enough, they located in regions situated near the pole. Peregrinus records this opinion, which he criticises and rejects, saying in Chapter X. that persons who hold such a doctrine "are ignorant of the fact that in many different parts of the globe the lodestone is found; from which it would follow that the needle should turn in different directions, according to the locality, which is contrary to experience." A little further on he gives his own view, saying: "It is evident from the foregoing chapters that we must conclude that not only from the north pole (of the world), but also from the south pole rather than from the veins of mines, virtue flows into the poles of the lodestone."

Observations had to accumulate and much experimentation had to be done before it was finally established that the cause of the directive property of the magnet is not to be sought in the remote star depths at all, but in the earth itself, the whole terrestrial globe acting as a colossal magnet, partly in virtue of magnetic ore lying near the surface and partly also in virtue of electrical currents, due to solar heat, circulating in the crust of the earth.

Of the early years of Pierre le PÉlÉrin (Petrus Peregrinus), nothing is known save that he was born of wealthy parents in Maricourt, a village of Picardy in Northern France. From his academic title of Magister, we infer that he received the best instruction available at the time, probably in the University of Paris, which was then in the height of its fame. His reputation for mathematical learning and mechanical skill crossed the Channel and reached Friar Bacon in the University of Oxford. In his "Opus Tertium," the Franciscan Friar records the esteem in which he held his Picard friend, saying: "I know of only one person who deserves praise for his work in experimental philosophy, because he does not care for the discourses of men or their wordy warfare, but quietly and diligently pursues the works of wisdom. Therefore it is that what others grope after blindly, as bats in the evening twilight, this man contemplates in all their brilliancy because he is master of experiment."

Continuing the appraisal of his Gallic friend's achievements, he says: "He knows all natural sciences, whether pertaining to medicine and alchemy or to matters celestial and terrestrial. He has worked diligently in the smelting of ores and also in the working of minerals; he is thoroughly acquainted with all sorts of arms and implements used in military service and in hunting, besides which he is skilled in agriculture and also in the measurement of lands. It is impossible to write a useful or correct treatise on experimental philosophy without mentioning this man's name. Moreover, he pursues knowledge for its own sake; for if he wished to obtain royal favor, he could easily find sovereigns to honor and enrich him."

This is at once a beautiful tribute to the work and character of Peregrinus and an emphatic recognition of the paramount importance of laboratory methods for the advancement of learning. It is evident from such testimony, coming as it does from an eminent member of the brotherhood of science, that the world had not to wait for the advent of Chancellor Bacon or for the publication of his Novum Organum in 1620, to learn how to undertake and carry out a scientific research to a reliable issue. Call the method what you will, inductive, deductive or both, the method advocated by the Franciscan friar of the thirteenth century was the one followed at all times from Archimedes to Peregrinus and from Peregrinus to Gilbert, none of whom knew anything of Lord Bacon's pompous phrases and lofty commendation of the inductive method of inquiry for the advancement of physical knowledge. Be it said in passing, that Bacon, eminent as he undoubtedly was in the realm of the higher philosophy, was, nevertheless, neither a mathematician nor a man of science; he never put to a practical test the rules which he laid down with such certitude and expectancy for the guidance of physical inquiry. Moreover, there is not a single discovery in science made during the three centuries that have elapsed since the promulgation of the Baconian doctrine that can be ascribed to it; it has been steadily ignored by men renowned in the world for their scientific achievements and has been absolutely barren of results.

Peregrinus, on the other hand, does not stop to enumerate opinions, he does not even quote Aristotle; but he experiments, observes, reasons and draws conclusions which he puts to the further test of experiment before finally accepting them. Then and then only does he rise from the order of the physicist to that of the philosopher, from correlating facts and phenomena to the discovery of the laws which govern them and the causes that produce them. Furthermore, he was in no hurry to let the world know that he was grinding lodestones one day and pivoting compass-needles the next; what he cared for supremely was to discover facts, new phenomena, new methods. Peregrinus was not an essayist, nor was he a man of mere book-learning. He was a clear-headed thinker, a close and resourceful worker, a man who preferred facts to phrases and observation to speculation.

At one period of his life, Master Peter applied his ingenuity to the solution of a problem in practical optics, involving the construction of a burning-mirror of large dimensions somewhat after the manner of Archimedes; but though he spent three years on the enterprise and a correspondingly large sum of money, we are not told by Friar Bacon, who mentions the fact, what measure of success was achieved. Bacon, however, avails himself of the occasion to insinuate a possible cause of failure, for he says that nothing is difficult of accomplishment to his friend unless it be for want of means.

Centuries later, the French naturalist Buffon took up the same optical problem, with a view to showing that the feat attributed to Archimedes during the siege of Syracuse by the Romans was not impossible of accomplishment. For this purpose, he used 168 small mirrors in the construction of a large concave reflector, with which he ignited wood at a distance of 150 feet and succeeded in melting lead at a distance of 140 feet. As this was done in the winter time in Paris, it was concluded that it would have been quite possible to set a Roman trireme on fire from a safe distance by the concentrated energy of a Sicilian sun.

If Peregrinus was alert in mind, he appears to have been very active in body. Prompted, no doubt, by the higher motives of Christian faith and perhaps a little, too, by his fondness for travel and adventure, he took the cross in early life and joined one of the crusading expeditions of the time. That he went to the land of the paynim, we have no direct evidence; but we infer the fact from the title of Peregrinus or Pilgrim, by which he is known, his full name being Pierre le PÉlÉrin de Maricourt, or, in the Latinized form, Petrus Peregrinus de Maricourt.

In 1269, we find him engaged in a military expedition undertaken by Charles Duke of Anjou, for the purpose of bringing back to his allegiance as King of the Two Sicilies the revolted city of Lucera in Southern Italy. He served in what might be called the engineering corps of the army, and was engaged in fortifying the camp and constructing engines of defense and attack. Unlike his companions in arms, Peregrinus does not allow himself to be wholly absorbed with military duties, nor does he waste his leisure hours in frivolous amusements; his mind is on higher things; he is engrossed with a problem in practical mechanics which required him to devise a piece of mechanism that would keep an armillary sphere in motion for a time.

In outlining the necessary mechanism, as he conceived it, he was gradually led to consider the general and more fascinating problem of perpetual motion itself, with the result that he waxed somewhat enthusiastic when he thought that he saw the possibility of constructing an ever-turning wheel in which the motive power would be magnetic attraction, the attraction of a lodestone for a number of iron teeth arranged at equal distances on the periphery of a wheel. The device looked well on paper, beyond which stage it was not carried, perhaps for want of leisure, or more probably for want of the necessary material and tools. Had Peregrinus been able to test his theoretical views on the magnetic motor by actual experiment, the delusive character of perpetual motion would have been recognized at an early epoch in the world's history, and much time and money spared for more profitable investment.

This very wheel, which was designed in the trenches before Lucera in 1269, was probably the cause of the withering rebuke which Justin Huntly McCarthy administers in his "History of the French Revolution," Vol. I., p. 256, where he says: "In the long record of rascaldom from Peregrinus to Bamfylde Moore Carew, no single rascal stands forward with such magnificent effrontery, such majestic impudence, such astonishing success as Cagliostro." To say the least, this is a very serious slip of the pen on the part of the Irish historian of the French Revolution, in which a scientific pioneer of the first rank and a patriot of exalted type is mistaken for a charlatan of the deepest dye.

Although Peregrinus puts the burden of constructing his wheel on others, he does not appear to have considered it a vain conceit; for, in the beginning of the last chapter of the "Epistola" he says: "In this chapter, I will make known to you the construction of a wheel which, in a remarkable manner, moves continuously." He is writing from Southern Italy to his friend Siger (Syger, Sygerus), at home in Picardy; and that this friend may the better comprehend the mechanism of the wheel, he proceeds to describe in a systematic manner the various properties of the lodestone, all of which he had investigated and many of which he had discovered. The "Epistola" of Peregrinus is, therefore, the first treatise on the magnet ever written; it stands as the first great landmark in magnetic philosophy.

The work is divided into two parts—the first contains ten chapters and the latter three. "At your request," he says to his friend, "I will make known to you in an unpolished narrative the undoubted though hidden virtue of the lodestone, concerning which philosophers, up to the present time, give us no information. Out of affection for you, I will write in simple style about things entirely unknown to the ordinary individual."

After this declaration as to the original character of his work Peregrinus proceeds: "You must know that whoever wishes to experiment should be acquainted with the nature of things; he must also be skilled in manipulation, in order that by means of this stone, he may produce those marvelous results."

The titles of the chapters will give an idea of the comprehensive character of the magnetic work accomplished by the author and, at the same time, will serve to show how much was known about the lodestone in the thirteenth century.

PART I.
Chap. I. Purpose of this work.
II. Qualifications of the experimenter.
III. Characteristics of a good lodestone.
IV. How to distinguish the poles of a lodestone.
V. How to tell which pole is north and which south.
VI. How one lodestone attracts another.
VII. How iron touched by a lodestone turns towards the
poles of the world.
VIII. How a lodestone attracts iron.
IX. Why the north pole of one lodestone attracts the south
pole of another, and vice versa.
X. An inquiry into the natural virtue of the lodestone.
PART II.
Chap. I. Construction of an instrument for measuring the azimuth
of the sun, the moon or any star when in
the horizon.
II. Construction of a better instrument for the same purpose.
III. The art of making a wheel of perpetual motion.

An attentive reading of the thirteen chapters of this treatise of 3,500 words will show that:

(1) Peregrinus assigns a definite position to what he calls the poles of a lodestone and gives practical directions for determining which is north and which south.

(2) He establishes the two fundamental laws of magnetism, that like poles repel and unlike poles attract each other.

(3) He demonstrates by experiment that every fragment of a lodestone is a complete magnet, and shows how the fragments should be put together in order to reproduce the polarity of the unbroken stone.

(4) He shows how a pole of a lodestone may neutralize a weaker one of the same name and even reverse its polarity.

(5) He pivots a magnetized needle and surrounds it with a circle divided into 360 degrees.

This brief summary shows the great advance made by the author on what was known about the lodestone before his time. Most of the salient facts in magnetism are clearly described and some of their applications pointed out. So thorough and complete was this apprehension and explanation of magnetic phenomena that nothing of importance was added to it for the next three hundred years.

In the compass which Peregrinus devised for use in navigation, a light magnetic needle was thrust through a slender vertical axis made of wood, which axis also carried a pointer of brass or silver at right angles to the needle. According to the belief of the time, the magnetic needle gave the north and south points of the horizon, while the brass pointer determined the east and west points. This compass, double pivoted be it noticed, was provided with a graduated circle and a movable arm, having a pair of upright pins at its extremities, which movable arm enabled the navigator to determine the magnetic bearing of the sun, moon or any star at the time of rising or setting. "By means of this instrument," the author says in Chap. II., "you can direct your course towards cities and islands and any other place wherever you may wish to go, by land or by sea, provided you know the latitude and longitude of the place which you want to reach."

The invention of the compass has been attributed to one Flavio Gioja, a seafaring man of Amalfi, a flourishing maritime town in Southern Italy. If we admit that Gioja was a real and not a fictitious person, we cannot, however, admit the claim which is made by his countrymen, when they say that he gave to the mariner the use of the compass in the year 1302; for we have seen that Peregrinus distinctly states that his compass, described in 1269, could be relied upon for guidance by the traveler on land as well as by the voyager on sea.

To Gioja may belong the merit of having simplified and improved the compass. It is likely that he suspended the needle on one pivot instead of the two used by Peregrinus, and that he added the compass-card with its thirty-two divisions, attaching it to the needle itself, thereby adding materially to the practical character of the compass as a nautical instrument.

On the other hand, a claim has been made for Peregrinus which cannot be admitted. It was put forward by his itinerant countryman ThÉvenot, in the seventeenth century, to the effect that the author of the "Epistola" was acquainted with magnetic declination, in virtue of which a freely suspended magnet does not point north and south, but cuts the geographical meridian at a definite angle.

Writing in 1681, ThÉvenot says in his "Recueil de Voyages" that: "It was a matter of general belief down to the present day, that the declination of the magnetic needle was first observed sometime in the beginning of the last (16th) century. I have found, however, that there was a declination of five degrees in the year 1269, having found it recorded in a manuscript with the title "Epistola Petri Adsigerii," etc.

The title of the manuscript seen by ThÉvenot is not, however, as he gives it above, but "Epistola Petri ad Sygerium," etc., which is quite a different reading.

There are twenty-eight manuscript copies of the "Epistola" known to exist; and only one of them, that of the University of Leyden, contains the passage alluded to by ThÉvenot. This manuscript was the object of careful study and critical examination by Wenckebach (1865) and other competent scholars, who pronounced it a spurious addition made some time in the early part of the 16th century.[4]

In the time of Peregrinus, it is probable that the declination did not exceed three degrees in Paris or on the shores of the Mediterranean, a quantity so small that it would have been difficult of detection; and, if detected, would have been attributed either to errors in the construction of the instrument used or to inaccuracy on the part of the observer. This is what happened to Columbus when, on his return to Spain, having reported the many and definite observations on the variation of the compass which he had made on his outward voyage, he was told by the learned ones of the day that he was in error and not the needle, because the latter was everywhere true to the pole.

This oft-stated and widely-believed fidelity of the needle to the pole is not, however, founded on fact; it is the exception, the rare exception, not the rule, despite the couplet of the poet:

or this other,

That the magnet does not turn to the pole of the world is common knowledge to-day, when the High School tyro will tell you that in New York it points 9° west of north, while in San Francisco it points 15° east of north. If he happens to be well up, he may refer to the position of the agonic line on the globe along which the needle stands true to the pole, while all places to the east of that line in our hemisphere have westerly declination and those to the west have easterly declination. Indeed, magnetic charts show places where the needle points east and west instead of north and south, and others where the north-seeking end points directly south. Such varying and conflicting behavior of the compass-needle serves to show the irregular manner in which the earth's magnetism is distributed and also the intensity of distributing forces which exist at certain places.

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° 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 flag-ship 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 to the west, to Castile.

The line of no variation, like all other isomagnetic lines, has shifted its position with time, so that it runs to-day considerably to the west of the place assigned to it by Columbus in 1492 and by the Papal Bull of the following year.

Columbus did not speak of the disquieting observation which he made on the night of the 13th of September; he thought of it, and wondered greatly what might be the cause of such an unexpected and untoward phenomenon. His silence on the matter did not avail, for the keen-eyed sailors noticed the westerly deflection of the needle when, after a few days, it became quite apparent. They grew alarmed, believing that the laws of nature were changing as they advanced farther and farther into the unknown. It was a trying moment for the Admiral, but his ingenuity and tactfulness rose to the occasion. He told his seamen that the needle did not point to the cynosure or last star in the tail of the Little Bear, as commonly supposed, but to a fixed point in the celestial sphere at which there was no star, adding that the "cynosure" itself, the Polaris of our days, was not stationary, but had a rotational movement of its own like all other heavenly bodies.

We do not know what Columbus thought of his explanation, born of the stress of the moment, but the esteem in which he was held by pilots and sailors alike for his knowledge of astronomy and cosmography led them to accept it. Their fears were allayed, a mutiny was averted and a successful termination to their voyage rendered possible.

Captains of ocean-liners would give to-day a different answer to a passenger who might consult them about the splinter of steel which serves to guide their fleet vessels in darkest nights, through howling tempests and over billowy seas. The mysterious influence that controls it, they would say, comes neither from Polaris nor the pole of the world, nor from the heavens above, but from the earth beneath.

Such an explanation was not thought of until it was clearly shown a hundred years later that this globe of ours acts like a colossal lodestone, controlling every magnet in our laboratories and observatories, and every needle on board the merchantmen and fighting-monsters that plough our seas and oceans.

Without any intuition of modern theory, Columbus made two discoveries in terrestrial magnetism, as we have seen, each of fundamental importance, whether considered from the view-point of pure science or that of practical navigation, viz., (a) that the needle is not true to the pole and (b) that the angular displacement of the needle from true orientation, the variation of the compass, as it is called in nautical parlance, differs with the place of the observer. These two discoveries as well as the location of a place of no variation on the Atlantic Ocean entitle Columbus to a prominent place among the founders of the science of terrestrial magnetism.

Later observers discovered that even for a given place this element of magnetic declination has not a constant value, but undergoes changes which complete their cycle, some in a day, others in a year, and others again in centuries. The last or secular change in the direction of the magnetic needle was discovered by Gellibrand, of London, in 1634 (published in 1635); the annual, by Cassini, at Paris, 1782-1791; and the diurnal, by Graham, of London, in 1722.

The first observation of magnetic declination on land appears to have been made about the year 1510 by George Hartmann (1489-1564), Vicar of the Church of St. Sebald in Nuremberg, who found it to be 6° east in Rome, where he was living at the time. Hartmann's observation of the declination in Rome and also in Nuremberg, where the needle pointed 10° east of north, will be found in a letter which he wrote in 1544 to Duke Albert of Prussia and which remained unpublished until the year 1831.

Returning to the treatise of Peregrinus on the magnet, it should be said that for several centuries the twenty-eight manuscript copies lay undisturbed on the dusty shelves of city and university libraries. In 1562, four years after the appearance of the first printed edition (Augsburg, 1558), Taisnier, a Belgian writer on magnetics, who is also described as poet-laureate and Doctor "utriusque juris," was among the earliest to discover the "Epistola," from which he copied extensively in his little quarto on the magnet and its effects, thus showing that there were literary pirates in those days. It was also well known to Gilbert, to Cabeo and Kircher; but despite the references of these writers, the "Epistola" remained practically unknown until Cavallo, of London, called attention to the Leyden manuscript in the third edition of his "Treatise on Magnetism,"[5] 1800, by giving part of the text and accompanying it with a translation.

Later, in 1838, Libri, historian of the mathematical sciences in Italy, gave excerpts from the Paris codex with translation; but the scholar who contributed most of all to make the work of Peregrinus known is the Italian Barnabite, Timoteo Bertelli, who published in 1868 a critical study of the various manuscripts of the letter, principally those which he found in Rome and in Florence, adding copious notes of historic, bibliographic and scientific value. Father Bertelli was Professor of Physics in the Collegio della Quercia, in Florence, where he took an active interest in Italian seismology besides carrying on investigations in meteorology, telegraphy and electricity. Born in Bologna in 1826, he died in Florence in March, 1905.

The following list of manuscript copies of the "Epistola" is taken from a scholarly paper by Professor Silvanus P. Thompson, of London, which appeared in the "Proceedings of the British Academy" for 1906:—

The first printed edition of the "Epistola" was prepared for the press in 1558 by Achilles Gasser, a man well versed in the science and philosophy of his day; another edition, which will probably be considered the textus receptus, is that which was prepared and published by Bertelli in 1868.

No complete translation in any language of this historical work on magnetism was made until 1902, when Prof. Silvanus P. Thompson, of London, published his "Epistle of Peter Peregrinus of Maricourt to Sygerus of Foncaucourt, soldier, concerning the Magnet." Unfortunately, this translation was printed for private circulation and limited to 250 copies. Two years later, 1904, Brother Arnold, F. S. C., presented a memoir on Peregrinus, including a translation of the "Epistola," for the M. Sc. degree of Manhattan College, New York City, which translation was published some months later by the McGraw Publishing Company, New York. These are the only complete translations of the "Letter" of Peregrinus on the Magnet which have yet appeared.

Brother Potamian.