The Astronomy of Milton's 'Paradise Lost', Thomas Nathaniel Orchard [best selling autobiographies .TXT] 📗

38]"> As the chief expounder of the new philosophy, Galileo had to encounter the prejudices of the followers of Aristotle, and of all those who disliked any innovation or change in the established order of things. The antagonism which existed between Galileo and his opponents, who were both numerous and influential, was intensified by the bitterness and sarcasm which he imparted into his controversies, and the attitude assumed by his enemies at last became so threatening that he deemed it prudent to resign the Chair of Mathematics in the University of Pisa.

In the following year he was appointed to a similar post at Padua, where his fame attracted crowds of pupils from all parts of Europe.

In 1611 Galileo visited Rome. He was received with much distinction by the different learned societies, and was enrolled a member of the Lyncæan Academy. In two years after his visit to the capital he published a work in which he declared his adhesion to the Copernican theory, and openly avowed his disbelief in the astronomical facts recorded in the Scriptures. Galileo maintained that the sacred writings were not intended for the purpose of imparting scientific information, and that it was impossible for men to ignore phenomena witnessed with their eyes, or disregard conclusions arrived at by the exercise of their reasoning powers.

The champions of orthodoxy having become alarmed, an appeal was made to the ecclesiastical authorities to assist in suppressing this recent astronomical heresy, and other obnoxious doctrines, the authorship of which was ascribed to Galileo.

In 1615, Galileo was summoned before the Inquisition to reply to the accusation of heresy. ‘He was charged with maintaining the motion of the Earth and the stability of the Sun; with teaching this doctrine to his pupils; with corresponding on the subject with several German mathematicians; and with having published it, and attempted to reconcile it to Scripture in his letters to Mark Velser in 1612.’

These charges having been formally investigated by the Inquisition, Cardinal Bellarmine was authorised to communicate with Galileo, and inform him that unless he renounced the obnoxious doctrines, and promised ‘neither to teach, defend, or publish them in future,’ it was decreed that he should be committed to prison. Galileo appeared next day before the Cardinal, and, without any hesitation, pledged himself that for the future he would adhere to the pronouncement of the Inquisition.

Having, as they imagined, silenced Galileo, the Inquisition resolved to condemn the entire Copernican system as heretical; and in order to effectually accomplish this, besides condemning the writings of Galileo, they inhibited Kepler’s ‘Epitome of the Copernican System,’ and Copernicus’s own work, ‘De Revolutionibus Orbium Celestium.’

Whether it was that Galileo regarded the Inquisition as a body whose decrees were too absurd and unreasonable to be heeded, or that he dreaded the consequences which might have followed had he remained obstinate, we know that, notwithstanding the pledges which he gave, he was soon afterwards engaged in controversial discussion on those subjects which he promised not to mention again.

On the accession of his friend Cardinal Barberini to the pontifical throne in 1623, under the title of Urban VIII., Galileo undertook a journey to Rome to offer him his congratulations upon his elevation to the papal chair. He was received by his Holiness with marked attention and kindness, was granted several prolonged audiences, and had conferred upon him several valuable gifts.

Notwithstanding the kindness of Pope Urban and the leniency with which he was treated by the Inquisition, Galileo, having ignored his pledge, published in 1632 a book, in dialogue form, in which three persons were supposed to express their scientific opinions. The first upheld the Copernican theory and the more recent philosophical views; the second person adopted a neutral position, suggested doubts, and made remarks of an amusing nature; the third individual, called Simplicio, was a believer in Ptolemy and Aristotle, and based his arguments upon the philosophy of the ancients.

As soon as this work became publicly known, the enemies of Galileo persuaded the Pope that the third person held up to ridicule was intended as a representation of himself—an individual regardless of scientific truth, and firmly attached to the ideas and opinions associated with the writings of antiquity.

Almost immediately after the publication of the ‘Dialogues’ Galileo was summoned before the Inquisition, and, notwithstanding his feeble health and the infirmities of advanced age, he was, after a long and tedious trial, condemned to abjure by oath on his knees his scientific beliefs.

‘The ceremony of Galileo’s abjuration was one of exciting interest and of awful formality. Clothed in the sackcloth of a repentant criminal, the venerable sage fell upon his knees before the assembled cardinals, and, laying his hand upon the Holy Evangelists, he invoked the Divine aid in abjuring, and detesting, and vowing never again to teach the doctrines of the Earth’s motion and of the Sun’s stability. He pledged himself that he would nevermore, either in words or in writing, propagate such heresies; and he swore that he would fulfil and observe the penances which had been inflicted upon him.’ ‘At the conclusion of this ceremony, in which he recited his abjuration word for word and then signed it, he was conveyed, in conformity with his sentence, to the prison of the Inquisition.’[2]

Galileo’s sarcasm, and the bitterness which he imparted into his controversies, were more the cause of his misfortunes than his scientific beliefs. When he became involved in difficulties he did not possess the moral courage to enable him to abide by the consequences of his acts; nor did he care to become a martyr for the sake of science, his submission to the Inquisition having probably saved him from a fate similar to what befell Bruno. Though it would be impossible to justify Galileo’s want of faith in his dealings with the Inquisition, yet one cannot help sympathising deeply with the aged philosopher, who, in this painful episode of his life, was compelled to go through the form of making a retractation of his beliefs under circumstances of a most humiliating nature.

But the persecution of Galileo did not delay the progress of scientific inquiry nor retard the advancement of the Copernican theory, which, after the discovery by Newton of the law of gravitation, was universally adopted as the true theory of the solar system.

Ferdinand, Duke of Tuscany, having exerted his influence with Pope Urban on behalf of Galileo, he was, after a few days’ incarceration, released from prison, and permission was given him to reside at Siena, where he remained for six months. He was afterwards allowed to return to his villa at Arcetri, and, though regarded as a prisoner of the Inquisition, was permitted to pursue his studies unmolested for the remainder of his days.

Galileo died at Arcetri on January 8, 1642, when in the seventy-eighth year of his age.

Though not the inventor, he was the first to construct a refracting telescope and apply it to astronomical research. With this instrument he made a number of important discoveries which tended to confirm his belief in the truthfulness of the Copernican theory.

On directing his telescope to the Sun, he discovered movable spots on his disc, and concluded from his observation of them that the orb rotated on his axis in about twenty-eight days. He also ascertained that the Moon’s illumination is due to reflected sunlight, and that her surface is diversified by mountains, valleys, and plains.

On the night of January 7, 1610, Galileo discovered the four moons of Jupiter. This discovery may be regarded as one of his most brilliant achievements with the telescope; and, notwithstanding the improvement in construction and size of modern instruments, no other satellite was discovered until near midnight on September 9, 1892, when Mr. E. E. Barnard, with the splendid telescope of the Lick Observatory, added ‘another gem to the diadem of Jupiter.’

The phases of Venus and Mars, the triple form of Saturn, and the constitution of the Milky Way, which he found to consist of a countless multitude of stars, were additional discoveries for our knowledge of which we are indebted to Galileo and his telescope. Galileo made many other important discoveries in mechanical and physical science. He detected the law of falling bodies in their accelerated motion towards the Earth, determined the parabolic law of projectiles, and demonstrated that matter, even if invisible, possessed the property of weight.

In these pages a short historical description is given of the progress made in astronomical science from an early period to the time in which Milton lived. The discoveries of Copernicus, Kepler, and Galileo had raised it to a position of lofty eminence, though the law of gravitation, which accounts for the form and permanency of the planetary orbits, still remained undiscovered. Theories formerly obscure or conjectural were either rejected or elucidated with accuracy and precision, and the solar system, having the Sun as its centre, with his attendant family of planets and their satellites revolving in majestic orbits around him, presented an impressive spectacle of order, harmony, and design.

CHAPTER II ASTRONOMY IN THE SEVENTEENTH CENTURY

The seventeenth century embraces the most remarkable epoch in the whole history of astronomy. It was during this period that those wonderful discoveries were made which have been the means of raising astronomy to the lofty position which it now occupies among the sciences. The unrivalled genius and patient labours of the illustrious men whose names stand out in such prominence on the written pages of the history of this era have rendered it one of the most interesting and elevating of studies. Though Copernicus lived in the preceding century, yet the names of Tycho Brahé, Kepler, Galileo, and Newton, testify to the greatness of the discoveries that were made during this period, which have surrounded the memories of those men with a lustre of undying fame.

Foremost among astronomers of less conspicuous eminence who made important discoveries in this century we find the name of Huygens.

Christian Huygens was born at The Hague in 1629. He was the second son of Constantine Huygens, an eminent diplomatist, and secretary to the Prince of Orange. Huygens studied at Leyden and Breda, and became highly distinguished as a geometrician and scientist. He made important investigations relative to the figure of the Earth, and wrote a learned treatise on the cause of gravity; he also determined with greater accuracy investigations made by Galileo regarding the accelerated motion of bodies when subjected to the influence of that force.

Huygens admitted that the planets and their satellites attracted each other with a force varying according to the inverse ratio of the squares of their distances, but rejected the mutual attraction of the molecules of matter, believing that they possessed gravity towards a central point only, to which they were attracted. This supposition was at variance with the Newtonian theory, which, however, was universally regarded as the correct one.

Huygens originated the theory by which it is believed that light is produced by the undulatory vibration of the ether; he also discovered polarization.

Up to this time the method adopted in the construction of clocks was not capable of producing a mechanism which measured time with sufficient accuracy to satisfy the requirements of astronomers. Huygens endeavoured to supply this want, and applied his mechanical ingenuity in constructing a clock that could be relied upon to keep accurate time. Though the pendulum motion was first adopted by Galileo, he was unable to arrange its mechanism so that it should keep up a continuous movement. The oscillation of the pendulum ceased after a time, and a fresh impulse had to be applied to set it in motion. Consequently, Galileo’s clock was of no service as a timekeeper.

Huygens overcame this difficulty by so arranging the mechanism of his clock that the balance, instead of being horizontal, was directed perpendicularly, and prolonged