And later on, when great nations had been formed out of the tribes that once roamed in lawless and hostile bands, the wonders of nature were still regarded with the same awe, and it was even considered impious to question their cause or study their effect.

The wonderful succession of day and night, the recurrence of the seasons, the sun and moon, the stars and the winds and the tides, and all things else, were only a part of the great mystery of life, and all equally incomprehensible, from the flaming comet that illumined the heavens with unnatural brightness to the opening of the first bud or the fall of the first snowflake; and it was never dreamed that the time would come when man would look upon these things with any feeling but amazement.

And even when the world had grown wise in many ways, and there were great cities ruled and kept by powerful kings and mighty armies, and while poets and painters were making immortal poems and pictures, and man had learned to use the winds and the tides to guide him on his journeys, still the unexplained marvels of the universe were clothed in sacred mystery, and only the priests and astrologers dared to study and proclaim their laws.

From time to time some philosopher, seeking earnestly after the truth, would assert that he had discovered some secret of nature that would lead to the better understanding and use of her laws but the world seemed so enchanted with its own ignorance that the new discoveries were either received with unbelief, or the author accused of impiety and perhaps sentenced to death.

And so long centuries passed away while man seemed to the gain knowledge of every other kind, but held the world of nature still in childish wonder, and was as much terror-stricken by the sight of a comet or the eclipse of the sun as had been his remote ancestors who dwelt in caves and went naked through the wilderness in search of food.

But there came an age at last when knowledge had so increased and was so widely diffused among people of every class, that the rulers and priests of a country could no longer prevent any new discovery from being made known.

Every city boasted of schools and universities, and in them were found not only the great scholars and philosophers, but students from every class, for ignorance was no longer considered desirable, and it was esteemed to be able to talk of history and literature, the fine arts and philosophy. These universities were frequented by visitors from all parts of the civilized world, and thus it happened that any newly discovered scientific truth or theory was at once carried to remote places, and in this manner the systems taught in one city soon became known to the others, and knowledge greatly advanced by their mutual intercourse. About the middle of the sixteenth century the universities of Italy held a high rank among institutions of learning, and within their walls could be found some of the most earnest and enlightened thinkers of the world. Many of these gave their days and nights to the study of nature, and strove with untiring zeal to grasp the secrets that had eluded the wise of other ages.

Among these restless and inquiring spirits was Galileo Galilei, a youth of Pisa, who had entered the university of his native town at the age of nineteen as a student of medicine.

Although the father of Galileo was not wealthy, and a unversity education for his son would call for considerable denial on his part, still the effort was cheerfully made, and the rapid progress of the young student immediately proved the wisdom of the step.

From his earliest childhood Galileo had shown the greatest talent for mechanical invention, his wonderful toys and little models of machinery being the admiration and delight of his companions, and as he grew older this talent developed more and more, and led to some of the most important inventions in the history of mechanics.

Two years after his entrance at the university he noticed one day, while sitting in the cathedral, a lamp swinging from the roof, and keeping as it swung a regular and uniform motion. This circumstance, which would never have attracted the notice of the careless observer, at once held the attention of the young inventor, and he watched the lamp until he became convinced, by comparing its motion with the beating of his pulse, that its vibrations, whether great or small, recurred at regular and equal intervals. He immediately saw that this discovery might lead to some useful mechanical invention, and at once set about verifying it by different experiments; the results proved the truth of his supposition, and it then occurred to him that if he were able to reckon the vibrations of a swinging body from the beat of a normal pulse, he might be able to do the reverse to ascertain the pulse of a patient by comparing it with the same vibrations. He at once constructed a simple instrument to test his theory, and the experiment proved so satisfactory that the invention at once passed into common use by all the physicians of the day.

This first pendulum—which was called a pulsilogy, from the use it was put to—consisted simply of a weight attached to a string, and a graduated scale. The string was gathered up in the hand till the vibrations of the weight coincided with the beating of the pulse, and it was then reckoned from the scale whether the rate were normal or otherwise.

Although the pendulum was invented for the sole purpose of assisting in the practice of medicine, yet the discovery of its principle by led to important results; previous to this there had been many contrivances for the measurement of time, hour-glasses, sun-dials, water-dials, burning candles, and other expedients succeeding each other in turn, but none of these had been able to measure time so accurately as the pendulum, and its use in dividing the day, and in astronomical observations soon became indispensable. Its invariable regularity was of the greatest service to the astronomers, who, by means of the pendulum-clock which was invented some years later by Huygens, a Dutch astronomer, were able to make calculations more exactly and satisfactorily than ever before, and the same instrument in time led to the knowledge of the real form of the earth. Thus the first invention of Galileo not only served the practical needs of daily life but was the means of advancing scientific observation to a plane inaccessible before.

Although Galileo had entered the university as a student of medicine this subject gradually lost all charm for him, and he devoted himself more and more exclusively to mathematics and physics. This change was at first unwelcome to his father, but as time passes and he saw that his son was irresistibly carried on by his new pursuits, he no longer opposed him, and allowed him to devote his time to the study of natural philosophy.

An essay on physics brought Galileo to the notice of one of the leading mathematicians of Italy, and through his influence the young philosopher was appointed to the lectureship of mathematics at Pisa. This new position did not prevent his pursuing his studies with undiminished vigor, and his lectures attracted immediate attention. Almost from the beginning of his university career, Galileo showed that boldness and originality of thought which distinguished him in after-life, and won the ill-will of several of the professors by his unwillingness to accept for truth many of the dogmas which they held sacred.

But Galileo had been brought up under the influence of a father who was accustomed to give full and free discussion to any subject that occupied his mind, and this training, together with his own original genius, made it impossible for the son to follow easily in the beaten paths of university life, and thus thrown back upon himself, and with only the help and sympathy of one or two of his companions, he began to find out new lines of thought, and to follow paths that had hitherto been considered unlawful.

New ways of solving old questions presented themselves freely to his inquiring mind, and were tested, and, when found satisfactory, accepted with the same readiness that was accorded the old faiths, and this could not be forgiven by the professors, who considered it the most honorable thing in the world to receive the ancient philosophies without question or disparagement, and whose greatest ambition it was to discover or wring some new meaning out of the old texts that would apply to all doubts and settle all discussion. And thus from the beginning of his career, Galileo was surrounded by the enemies of progress, and even his mechanical investigations were received with cold favor.

But this did not daunt him, and as he in his studies he subjected all the propositions of the old philosophy to the severe test of free investigation, glad when he could find no flaw in the world-old wisdom, but gladder still when he discovered an error the righting of which would lead thought into wider and purer channels. And the responsibility of his position as a teacher made him the more anxious to sift out the good from the bad, while the opportunity thus offered of influencing a younger generation made him strive with renewed earnestness after the truth.

These efforts only served to increase the hospitality that the professors had shown toward him in his student-days; but Galileo persisted in his investigations, and proved the folly of some of their most cherished beliefs, announcing the results of his experiments with a persistent dertermination and faith that won many adherents. But his enemies would not listen even when his arguments were followed by the most conclusive proofs; and on one occasion, when Galileo performed the experiment of letting two bodies of different weight, fall simulataneously from the leaning tower of Pisa, in order to prove that they would reach the ground at the same time, his angry opponents refused to believe the evidence of their own eyes, and quoted in reply the sentence from Aristotle which asserted that if two different weights were let fall from the same height the heavier one would reach the ground sooner. Such obstinancy, combined with ill-will and distrust, rendered Galileo's position at Pisa so unpleasant that, when an opportunity offered for him to take the chair of mathematics at Padua, he did not hesitate, and left Pisa after having taught there only three years.

He now began to circulate his writings more freely, one essay following another with such rapidity, and all embodying such new and startling theories, that his name soon became familiar to the scientific world, and his opinions were listened to with a respect that roused the fiercest resentment of his enemies.

One of the most sacred beliefs of the day was the Plotemaic [should be Ptolemaic instead of Plotemaic] theory that the earth was the centre of the universe, and that the sun, moon, planets, and stars all revolved around it, outside of the atmospheres of air and fire which immediately surrounded it.

Many absurd reasons were given to prove the truth of this theory, and philosophers seemed willing to accept anything as fact, provided it coincided with this popular superstition, and even gravely acquiesced when it was asserted that the earth must  be the centre of the universe because it was the only planet that had a moon. This theory took its name from Claudius Ptolemy, an old astronomer and geographer, who lived at Alexandria about the middle of the second century Ptolemy gave innumerable reasons for his belief, and said that it would be impossible and absurd to believe otherwise. About four hundred and fifty years Pythagoras, a Greek philosopher, who spent many years studying in Egypt, and who was familiar with the astronomical theories of the Chaldeans and Egyptians, proclaimed to his disciples that the earth had a motion and revolved periodically around a great central fire, and this theory met with the warmest approbation of some other Greek philosophers, who also believed in two motions of the earth, an annual and daily, and claimed that the heavens only appeared to move because the earth turned on its axis with such rapidity.

But this belief was rejected with scorn by Ptolemy, who said that it was impossible to believe that the earth turned on its axis from west to east during twenty-four hours; for if it were true, then bodies lighter than the earth and suspended in the air, would have an opposite movement, and that it would thus be impossible for clouds or birds, and any object thrown in the air to go toward the east, as the earth would be constantly going before them and make it seem as if everything were going toward the west. And for two thousand years the world clung to the Ptolemaic theory, in part because it seemed reasonable and convincing, but chiefly because it had received the sanction of Aristotle, the greatest of the Greek philosophers, whose influence upon thought was so unlimited that even his most absurd theories of mechanics were received without question.

But in 1543 Nicholas Copernicus, a Prussian astronomer, published his great work "De Revolutionibus"—concerning the revolutions—in which he entirely refuted the Ptolemaic theory, and asserted that the earth was not the centre of the universe, and that it had a daily rotation on its axis and an annual revolution around the sun, which two motions accounted for all the other phenomena of the heavens, and satisfactorily explained all the hitherto unexplainable mysteries in regard to the motions of the heavenly bodies.

The opinions of Copernicus were received with disdain by the philosophers of the old school, and his work was derided as the wildest nonsense; but the more thoughtful minds gave his writings careful attention, and came gradually to accept his incontrovertible arguments, and among these was Galileo, who found it impossible to hold the Ptolemaic theory after becoming familiar with the works of Copernicus.

His conversion to the true theory was not, however, made publicly known at once, either because he felt that he had not yet sufficiently studied it, or because he feared that the opposition of his enemies might do the new system more harm than it would be in his power to overbalance.

But in 1604 the scientific world was startled by the sudden appearance of a new star, whose splendor at once attracted the attention of all astronomers. Night after night its brilliant light, changing from orange to yellow, purple, red, and white successively, illumined the heavens with new glory, and records were searched and old treatises pored over in order to see how often similar appearances had been noticed before.

Galileo studied the star with the greatest interest, and his lecture-rooms were crowded when it was announced that he would give a public explanation of the wonder; but the crowds who had come to agree with old theories or idly speculate over ancient astronomical history, were rudely startled by Galileo's original views, which swept away many of the fondest illusions of the age, and proclaimed clearly a new and unwelcome advance in the study of the heavens.

It was generally believed that the new star was a meteor having its origin in the atmosphere, and that it was nearer the earth than the moon; but Galileo claimed that this was impossible, and proved, by exact calculations from the situation and appearance, that the star must be placed among the most distant of the heavenly bodies, and that the belief in its motion around the earth was contrary to true theory of the earth's revolution around the sun.

This view was received with scorn by the followers of Aristotle, who held that the sky was unchangeable, and that the stars were carried in hollow crystalline spheres around the earth, thus making it impossible to account for the new star in this manner. They also declared their opposition to the theory of the motion of the earth, and Galileo was called upon to defend the Copernican system. He did this with such zeal that the university was at once divided into two parties, one agreeing with the Aristotelians, and the other following Galileo and accepting the new doctrines with delight. The dispute went on for some years, and Galileo omitted no chance to proclaim his belief in the Copernican system, and to add new proofs to strengthen its hold upon the minds of others; and in 1609 an event occurred which enabled him to completely vindicate the truth of his new belief, and to convince all but the most obstinate that it would be no longer possible to hold to the old theories. This was the invention of the telescope, the use of which revealed the most startling wonders in the heavens, and demonstrated the truth of Galileo's belief to the fullest extent.

Previous to this astronomers had been obliged to depend entirely upon the naked eye for making all observations; and although the world had advanced in almost every other way, in this respect the Italian star-gazer of the sixteenth century had no advantage over the Chaldean shepherds who, ages before, had studied the mysteries of the heavens during their lonely night-watches. But the telescope changed all this, and revolutionized the study of astronomy. It brought to light unsuspected possibilities for research, and laid bare the secrets that had eluded man from the earliest times. Not only were the planets and stars that were already known brought nearer and rendered more familiar by closer observation, but even the most distant of the heavenly bodies shone with a new glory, that was not diminished by the discovery that, farther still beyond their circles, other stars even yet more beautiful swept through their limitless courses, and that what had before seemed only empty space was in reality filled with vast systems of worlds, which waited only the proper moment to reveal themselves in all their bewildering splendor.

It is claimed by some that Galileo's invention of the telescope was not strictly original, and that he only applied and improved upon an idea that had already been used to some extent in the manufacture of optical instruments.

But, however this may be, it is certain that the first telescope which Galileo made and pointed to the heavens created the greatest wonder in the scientific world, and was considered almost as much of a marvel as the discovery of a new world would have been.

This first telescope, which was called Galileo's tube, aroused public curiosity to the greatest height, and Galileo's house was thronged with visitors eager to satisfy their curiosity; the most extravagant and absurd stories were circulated, and all through Venice, where Galileo happened to be staying at the time, there was no talk of anything but the wonderful instrument which was thought to be possessed of almost magical powers. The news spread rapidly from place to place, and all the astronomers set themselves to making telescopes, though it was long before anyone could produce an instrument equal in excellence to those made by Galileo. And so great was the excitement over the new invention, that small telescopes were sold in the streets as curiosities, and the observatories were besieged with people who gave the astronomers no peace until they satisfied their incredulous wonder.

In the meantime Galileo ascended his tower night after night, and pointed his telescope towards the heavens which had so suddenly assumed such a new and intense interest. And the results showed that, although he had given his whole life to the study, he had really only just begun to learn anything of the marvels of creation. One mystery after another was unfolded to his wondering gaze, and even the objects that had once seemed familiar to him now disclosed such new characteristics as to appear almost strange.

This was especially true of his observations on Jupiter, a planet which, from its great size and brilliant light, had always attracted the attention of astronomers. Regarded at first by mankind simply as a splendid star whose beauty added another glory to the sky, it was studied with unusual care, and even when later philosophers denied its stellar character, it was still an object of intense interest to astronomers, who looked upon it as a mysterious presence wandering among the familiar stars, awing them by its majesty, and yet as little understood as the flittings of the will-o'-the-wisp among the fireflies in the meadow. And although its planetary character was fully established in the time of Galileo, the wonder in it had not yet ceased. Galileo brought it night after night under the range of the telescope, and was soon rewarded by the most startling discovery in astronomical science.

He noticed, at first, that there seemed to be three new stars situated very near to Jupiter, and further observation led to the discovery of a fourth. Careful study of that part of the heavens soon led to the astonishing disclosure that these small stars revolved around Jupiter, in the same way that the moon revolved around the earth; and Galileo, after verifying his theory by elaborate and continuous observations, announced the undreamed-of fact that Jupiter was attended by four moons.

This intelligence was received with undisguised amazement by all classes. The friends of Galileo and the advoctates of the Copernican system, at once joyfully accepted this new proof of the harmonious motions of the heavenly bodies, while his opponents were equally bitter in their denunciation, refusing to look through the telescope for fear it would convince them of their error, and, as usual, bringing forth the most absurd arguments in favor of their own obstinancy.

Galileo had named the satellites the Medicæan stars in honor of his patron, Cosmo di Medici, and one antagonistic philosopher gravely denied the willingness of nature to give Jupiter four moons simply for the sake of immortalizing the name of Medici, and said that the whole thing was an idle dream.

Another declared solemnly that he did not more surely know that he had a soul in his body, than that the moons were caused entirely by reflected rays of light, and claimed that Galileo's "thirst for gold" had alone led him to such an announcement.

And still another astronomer seriously demonstrated that it was contrary to the law of nature to have more than seven planets, and that therefore more than seven could not exist. He argued tha there were seven windows given to animals in the domicile of the head, to admit the air to the rest of the body to warm and nourish it, and that likewise, in the heavens there were two favorable stars, Venus and Jupiter; two unfavorable stars, Mars and Saturn; two luminaries, the sun and the moon; and alone undecided and indifferent. Also, that there were but seven metals, seven days in the week, and innumerable similar phenomena to prove that there could only be seven planets; summing up with the conclusion that the satellites were invisible to the naked eye, that they therefore could exercise no influence on the earth, that they were therefore useless, and therefore did not exist.

To this Galileo only replied that, however weighty the reasons might be that no more than seven planets could exist, they scarcely seemed sufficient to destroy the new ones when actually seen, and went on observing Jupiter.

His friends supported his theories as warmly as ever, and the controversy was kept up until the existence of the satellites was established beyond a doubt, when his enemies went to the other extreme and claimed that Galileo's observations were most imperfect, as there were really twelve satellites instead of four; and it was only when Jupiter moved to another part of the heavens, carrying his four moons with him, that they admitted that the original announcement was correct.

Galileo's observations of the moon also led to a fierce discussion, and philosophers again spent a great time in arguing and denying, with the usual results.

From its nearness to the earth, and the interesting phenomena connected with the various changes that it passed through every month, the moon had from the earliest times been an object of the greatest interest to man, who attributed mysterious power to its influence, and placed it among the divinities. And it still held its subtle attraction long after the old religions had passed away, for with the exception of the sun, it alone of all the heavenly bodies exercised an important influence in the concerns of daily life. Filling the heavens with its wonderous beauty long after the great god of day had set, it seemed like a beneficent spirit sent by some protecting power to guard the lonely watches of the night; while to the traveller on desert or mountain or sea, its beams came with friendly assurance of help and in braving the unseen perils of the darkness.

In the time of Galileo the popular belief concerning the moon was that it was a perfectly spherical body, with a surface as smooth and polished as a mirror, and that the dark parts of its surface were either the reflections of the forests and mountains of the earth, or caused by the interposition of opaque bodies floating between it and the sun, or, because of its nearness to the earth, the result of contact with certain terrestrial elements which marred its beauty and made it less pure than the bodies in the more remote heavens.

But Galileo's observations led him to the belief that the moon resembled the earth in structure, and that its dark portions were the shadows reflected from mountains and other inequalities in its surface; while he also claimed that it was probable that there were continents and oceans distributed over the surface similar to those on the earth, and that the faint shadow which was attached to the crescent moon, and filled out that part of the surface unlighted by the sun, was caused by the reflection of the earth's light, or earthshine. These theories were at once attacked by his opponents, who said that Galileo took delight in ruining the fairest works of nature, and utterly denied the existence of mountains on the moon, as their presence there would destroy its spherical shape.

Galileo replied that to conceive of the moon and the earth as perfectly spherical bodies would only detract from their use, in the plan of nature, for absolute smoothness and sphericity would make the earth only a vast, unblessed desert, void of animals, of plants, and of men; the abode of silence and inaction; senseless, lifeless, soulless, and stripped of all those ornaments which made it so beautiful. But this argument was derided by his enemies, who replied that the moon's surface was really smooth and unalterable in spite of all that Galileo could say, and that the parts which appeared hollow or sunken were in reality filled up with a crystal substance perfectly imperceptible to the senses, but still serving the purpose of giving to the moon her true spherical shape.

Galileo agreed to accept the theory of a crystal substance filling all irregularities, provided the philosophers would allow him to raise crystal mountains ten times higher than those he had actually seen and measured, and this nonsense effectually put an end to the crystalline theory.

In regard to Galileo's theory of earthshine his critics averred that it was untenable, because the earth was not a planet and did not revolve around the sun, or shine like the other planets, and ascribed the shadow to Venus or the fixed stars, or the rays of the sun shining through the moon. And thus the endless dispute went on, and all of Galileo's wonderful discoveries were received with scorn and unbelief by the enemies of progress, who bent all the powers of their minds to the refutation of the Copernican theory. But Galileo went on with his observations undisturbed by this opposition, and constantly announced new wonders.

He examined the Milky Way, and was the first to prove that its nebulous appearance was caused by the presence of myriads of stars, whose light reached to infinite distances beyond the system of the earth; and although this theory was of course disputed, it was firmly established by repeated observation, and this confirmed beyond a doubt the conjecture of Pythagoras that countless millions of stars circled continuously through their distant courses far beyond the vision of man.

Galileo subjected all of the planets in turn to his scrutinizing gaze, and one discovery followed another with astounding rapidity, so that there never ceased to be a new marvel to wonder at.

He detected the presence of Saturn's rings, although his glass was not strong enough to show him their real nature, and he supposed the planet to have two attendant stars; and a month later he announced the discovery of the phases of Venus, deducing from this fact another proof of the Copernican system. He also examined the fixed stars, and by careful comparison of their light with that of the planets decided that they did not receive their light from the sun, and he added still another argument to the doctrine of Copernicus by the discovery of the spots on the sun and their motion across its disc.

As early as 807 dark spots had been observed on the face of the sun, and for centuries after this phenomenon attracted the attention of astronomers. But all the curiosity was satisfied by the supposition that the dark body was simply caused by the passage of Mercury or some other small object across the sun's surface.

But Galileo claimed that the spots were in actual contact with the sun, and that they had a common and regular motion with which they revolved around the sun, which turned upon his axis once a month.

Here was another argument for the Copernican theory, and in consequence the new explanation of sun spots was received with little favor by the followers of Aristotle.

And thus in the midst of opposition and discouragement Galileo kept on his way, continually adding to the sum of scientific knowledge, and unwearying in his efforts to place natural science upon a more reasonable and comprehensible plane than it had before reached.

His observations included not only the phenomena of the heavens, but also those connected more intimately with the earth, and his essays extended over a great variety of subjects which had hitherto been treated only with ignorance or indifferent success.

The results of his work were published from time to time, and in 1632 the labor of his life was given to the world in the form of a book entitled, "The Dialogue on the Ptolemaic and Copernican Systems," in which were incorporated all his views on natural science, and his arguments in favor of rejecting many of the old theories of the universe and accepting the new.

And now the unpopularity which had always followed him found a new object for its hatred.

The book was received with the most intense ill-will by Galileo's enemies, many of whom occupied high positions in philosophical circles, and possessed an unbounded influence with the dignitaries of Church and State, and the "Dialogue of the Systems" was made the means of bringing the quarrel between the old and new philosophies to an issue.

The hatred of years had at last found its opportunity, and Galileo was summoned to Rome to answer the charge of heresy in teaching the doctrines of Copernicus, which were assumed by the Church to be in opposition to the revealed word of God.

Galileo was seventy years old, and his life had been spent in reverent study of the works of nature, but the conclusions he arrived at differered from those accepted by the theologians of the day, and his long and faithful devotion to science, and all his splendid discoveries, were simply regarded by his enemies as the work of a man who dared to dispute the holiest tenets of the Church, and to offer a scientific creed as opposed to the sacred beliefs of the Aristotelian philosophers.

The Inquisition, which was then the judicial tribunal of the Roman Catholic Church, examined Galileo upon his religious and scientific views, and pronounced them impious and heretical, and called upon him to renounce and abjure the most cherished convictions of his soul, or suffer the penalty that attended any persistent opposition to the Holy Office.

The subject of Galileo's abjuration has always been a matter of dispute, some contending that it was exhorted from him while undergoing torture at the hands of the officers of the Inquisition, and others claiming that the terms of abduration were dictated by the inquisitors themselves, and are not to be considered as expressing the recantation of Galileo.

But, however that may be, it is certain that an abjuration, that was considered sufficiently condemning by his enemies, was sworn to by Galileo in the presence of the officers of the Inquisition, and that his recantation saved him from imprisonment, and perhaps death.

The well-known anecdote that when Galileo rose from his knees after signing the abjuration he stamped the ground and whispered to one of his friends—"It [the world] does move, though"— is without foundation. Although copies of his abjuration were immediately circulated throughout Italy, and were ordered to be read in the universities, the Copernican system still kept its hold upon the minds of all advanced thinkers, and Galileo was still regarded as its most powerful advocate.

The fact that his abjuration did not cost him the respect and admiration of his friends, is sufficient evidence that it was obtained under circumstances that reflect little credit on the supporters of the Church, and admits the probability that, even in this terrible crisis, Galileo maintained his character as an uncompromising advocate of the new school of thought; and his judges can only place his whole brave and consistent life against the questionable practices of the Inquisition, to give a balance largely in his favor.

Galileo died in 1642, having been blind for five years before his death.

The malice of his enemies followed him to the end, and he was denied the privilege of making a will, and of burial in consecrated ground.

But this petty spite could not interfere with the sentence passed upon him by all the unbiased thinkers of his own and succeeding ages, that his life was one of noble devotion to his work, and that through his influence scientific inquiry was first led into the pure ways of reasonable thought, and the world of nature more fully and clearly revealed, and endowed with new and unimagined beauty.