Galileo was born at Pisa, in the year 1564, the year that Calvin and Michael Angelo died, four years after the birth of Bacon, in the sixth year of the reign of Elizabeth, and the fourth of Charles IX., about the time when the Huguenot persecution was at its height, and the Spanish monarchy was in its most prosperous state, under Philip II. His parents were of a noble but impoverished Florentine family; and his father, who was a man of some learning,--a writer on the science of music,--gave him the best education he could afford. Like so many of the most illustrious men, he early gave promise of rare abilities. It was while he was a student in the university of his native city that his attention was arrested by the vibrations of a lamp suspended from the ceiling of the cathedral; and before he had quitted the church, while the choir was chanting mediaeval anthems, he had compared those vibrations with his own pulse, which after repeated experiments, ended in the construction of the first pendulum,--applied not as it was by Huygens to the measurement of time, but to medical science, to enable physicians to ascertain the rate of the pulse. But the pendulum was soon brought into the service of the clockmakers, and ultimately to the determination of the form of the earth, by its minute irregularities in diverse latitudes, and finally to the measurement of differences of longitude by its connection with electricity and the recording of astronomical observations. Thus it was that the swinging of a cathedral lamp, before the eye of a man of genius, has done nearly as much as the telescope itself to advance science, to say nothing of its practical uses in common life.
Galileo had been destined by his father to the profession of medicine, and was ignorant of mathematics. He amused his leisure hours with painting and music, and in order to study the principles of drawing he found it necessary to acquire some knowledge of geometry, much to the annoyance of his father, who did not like to see his mind diverted from the prescriptions of Hippocrates and Galen. The certain truths of geometry burst upon him like a revelation, and after mastering Euclid he turned to Archimedes with equal enthusiasm. Mathematics now absorbed his mind, and the father was obliged to yield to the bent of his genius, which seemed to disdain the regular professions by which social position was most surely effected. He wrote about this time an essay on the Hydrostatic Balance, which introduced him to Guido Ubaldo, a famous mathematician, who induced him to investigate the subject of the centre of gravity in solid bodies. His treatise on this subject secured an introduction to the Grand Duke of Tuscany, who perceived his merits, and by whom he was appointed a lecturer on mathematics at Pisa, but on the small salary of sixty crowns a year.
This was in 1589, when he was twenty-five, an enthusiastic young man, full of hope and animal spirits, the charm of every circle for his intelligence, vivacity, and wit; but bold and sarcastic, contemptuous of ancient dogmas, defiant of authority, and therefore no favorite with Jesuit priests and Dominican professors. It is said that he was a handsome man, with bright golden locks, such as painters in that age loved to perpetuate upon the canvas; hilarious and cheerful, fond of good cheer, yet a close student, obnoxious only to learned dunces and narrow pedants and treadmill professors and zealous priests,--all of whom sought to molest him, yet to whom he was either indifferent or sarcastic, holding them and their formulas up to ridicule. He now directed his inquiries to the mechanical doctrines of Aristotle, to whose authority the schools had long bowed down, and whom he too regarded as one of the great intellectual giants of the world, yet not to be credited without sufficient reasons. Before the "Novum Organum" was written, he sought, as Bacon himself pointed out, the way to arrive at truth,--a foundation to stand upon, a principle tested by experience, which, when established by experiment, would serve for sure deductions.
Now one of the principles assumed by Aristotle, and which had never been disputed, was, that if different weights of the same material were let fall from the same height, the heavier would reach the ground sooner than the lighter, and in proportion to the difference of weight. This assumption Galileo denied, and asserted that, with the exception of a small difference owing to the resistance of the air, both would fall to the ground in the same space of time. To prove his position by actual experiment, he repaired to the leaning tower of Pisa, and demonstrated that he was right and Aristotle was wrong. The Aristotelians would not believe the evidence of their own senses, and ascribed the effect to some unknown cause. To such a degree were men enslaved by authority. This provoked Galileo, and led him to attack authority with still greater vehemence, adding mockery to sarcasm; which again exasperated his opponents, and doubtless laid the foundation of that personal hostility which afterwards pursued him to the prison of the Inquisition. This blended arrogance and asperity in a young man was offensive to the whole university, yet natural to one who had overturned one of the favorite axioms of the greatest master of thought the world had seen for nearly two thousand years; and the scorn and opposition with which his discovery was received increased his rancor, so that he, in his turn, did not render justice to the learned men arrayed against him, who were not necessarily dull or obstinate because they would not at once give up the opinions in which they were educated, and which the learned world still accepted. Nor did they oppose and hate him for his new opinions, so much as from dislike of his personal arrogance and bitter sarcasms.