Historic Inventions

by Rupert Sargent Holland

Settled at last at Florence his work as an astronomer steadily went forward. He discovered that the planet Venus had a varying crescent form, that there were small spots circling across the face of the sun, which he called sun-spots, and later that there were mountains on the moon. He also visited Rome, where he was received with the greatest good-will by Pope Paul V and his cardinals, and where he met the leading scientists of the capital.

But Galileo’s course was no less flecked with light and shade than were the sun and moon he studied. The envy of rivals soon spread false reports about him, and the professors at Pisa refused to accept the results of his studies. Then one of the latter stirred the religious scruples of the Dowager Grand Duchess by telling her that Galileo’s conclusion that the earth had a double motion must be wrong, since it was opposed to the statements of the Bible. Galileo heard of this, and wrote a letter in reply, in which he said that in studying the laws of nature men must start with what they could prove by experiments instead of relying wholly on the Scriptures. This was enough to set the machinery of his enemies in motion. Galileo’s teachings were pointed out as dangerous to the teachings of the Church, and the officers of the Inquisition began to consider how they might best deal with him. Certain of his writings were declared false and prohibited, and he was admonished that he must follow certain lines in his teachings. He went to Rome himself, and saw the Pope again, but found that his friends were fewer and his enemies growing more powerful.

The theory of Copernicus that the earth and planets are in constant motion was the very foundation of Galileo’s scientific studies, and yet the order of the Church now forbade him to use this theory. He went back to Florence out of health and despondent. His old students were falling away from him through fear of the Pope’s displeasure, and he was left much alone. But his thirst for knowledge would not let him rest. He took up his residence in the fine old Torre del Gallo, which looks down on Florence and the river Arno, and went on with his work. He wrote out the results of his discoveries, and made a microscope from a model he had seen. Soon he had greatly improved upon his model, and had an instrument, which, as he said, “magnifies things as much as 50,000 times, so that one sees a fly as large as a hen.” He sent copies to some friends, and shortly his microscopes were as much in demand as his telescopes had been.

In 1632 he published what he called “The Dialogues of Galileo Galilei.” This divided the world of Italy into two camps, the one those who believed in Aristotle and the old learning, the other those who followed Copernicus, Galileo, and Kepler. The Jesuits took up the gage he had thrown down, and Galileo found the Church of Rome arrayed against him. The sale of his book was forbidden, a commission was appointed to bring charges against him, and he was ordered to go to Rome for trial. The commission reported that Galileo had disobeyed the Church’s orders by maintaining that the earth moves and that the sun is stationary, that he had wrongly declared that the movements of the tides were due to the sun’s stability and the motion of the earth, and that he had failed to give up his old beliefs in regard to the sun and the earth as he had been commanded.

Galileo, although he was ill, went to Rome, and was placed on trial before the Inquisition. After weeks of weary waiting and long examinations he was ordered to take a solemn oath, forswearing his belief in his own writings and rejecting the conclusion that the sun was stationary and that the earth moved. Rather than suffer the pains of the Inquisition he agreed, and made his solemn declaration. According to an old story, now discredited, as he rose from his knees after the ceremony he whispered to a friend “Eppur si muove” (It does move, nevertheless). Whether he said this or not there can be no doubt but that the great astronomer knew the performance was a farce, and that the world did move in spite of all the Inquisition could declare.

The Inquisition did its work ruthlessly. Notices of the sentence prohibiting the reading of Galileo’s book and ordering all copies of it to be surrendered, and copies of the declaration he had made denying his former teachings, were sent to all the courts of Europe and to many of the universities. In Padua the documents were read to teachers and students at the university where for so many years Galileo had been the greatest glory of learning, and in Florence the Inquisitor read the sentence publicly in the church of Santa Croce, notices having been sent to all who were known to be friends or followers of Galileo, ordering them to attend. Thus his humiliation was spread broadcast, and in addition he was ordered to be held at Rome as a prisoner.

After a time he was permitted to go on parole to the city of Siena, which was at least nearer his home outside Florence. There he stayed until the Grand Duke Cosimo, who had stood by him, persuaded the Church that Galileo’s health required that he be allowed to join his friends. At last he reached his home, and again took up his studies. His eyesight was failing, and eventually he became entirely blind, but meanwhile his speculations covered the widest fields of science, he studied the laws of motion and equilibrium, the velocity of light, the problems of the vacuum, of the flight of projectiles, and the mathematical theory of the parabola. He wrote another book, dealing with two new sciences, and was busy with designs for a pendulum clock at the time of his death in 1642. He was buried in the church of Santa Croce, the Pantheon of Florence, under the same roof with his great fellow countryman, Michael Angelo.

What is known as the modern refracting telescope is based upon a different combination of lenses than that used by Galileo. Kepler studied Galileo’s instrument, and then designed one consisting of two convex lenses. The modern telescope follows Kepler’s arrangement, but Galileo’s adjustment is still suitable where only low magnifying powers are needed, and is used to-day in the ordinary field- and opera-glass.

Galileo knew nothing of what we call the reflecting telescope. He found that by using a convex-lens as an object-glass he could bring the rays of light from any distant object to a focus, and it did not apparently occur to him that he could achieve the same end by the use of a concave mirror. James Gregory, a Scotchman, designed the first reflector in 1663, and described it in a book, but he was too poor to construct it. Nine years later Sir Isaac Newton, having studied Gregory’s plans, built the first reflecting telescope, which is now to be seen in the hall of the Royal Society in London. But invention has gone yet farther in perfecting these instruments with which to study the skies, and the great telescopes of modern times have in most instances discarded Newton’s reflector for the refracting instrument. And these are built on a tremendous scale. The Yerkes telescope at Williams Bay, Wisconsin, has a refractor of forty inches, and the one built for the Paris Exposition of 1900, one of fifty inches. In numerous other details they have changed, and yet each is chiefly indebted to that simple spy-glass of Galileo, by which he was able to show the nobles and senators of Venice full-rigged ships, which without it were barely distant specks on the horizon. Or, going still farther back, the men who make our present telescopes are following the trail that was first blazed on the day when the Dutch apprentice of Middleburg chanced to pick up two spectacle lenses and look through the two of them at once.

Galileo made many great discoveries and inventions; there was hardly a field of science that he did not enter and explore; but his greatest work was to open a new world to men’s attention. It was this that brought him before the Inquisition and that branded him as a dangerous heretic, and it was this that placed him in the forefront of the world’s discoverers. Men might say that the earth stood still, because it suited them best to believe so, but Galileo gave the world an instrument by which it could study the matter for itself, and the world has gone on using that instrument and that method ever since.