346 



GALILEI. 



Mount of Christ); here was mount Tabor, where his 

 disciples saw him in his transfiguration. The inhabi- 

 tants of this country, on account of their ignorance and 

 simplicity of manners, were despised by the Jews, 

 who. by way of contempt, called Christians, at first, 

 Galileans, because their religion particularly pre- 

 vailed in Galilee. At present, Galilee, with the 

 other provinces of Palestine, forms a part of the 

 government of Damascus, in Syria or Soristan, and 

 languishes under the weight of Turkish oppression. 

 Bedouins and hordesof robbers swarm in the desolated 

 valleys, and only a few holy places are still guarded 

 by a few oppressed Christians. 



GALILEI, GALILEO, who has gained immor- 

 tality by his discoveries in natural philosophy, was 

 born, 1564, at Pisa. His father, Vincenzo Galilei, 

 a nobleman of Florence, caused him to be instructed 

 in the ancient languages, drawing, and music, and 

 he very early showed a strong inclination to 

 mechanical labours. In 1581, Galileo entered the 

 university of Pisa, to attend lectures on medicine 

 and the Aristotelian philosophy. The latter, loaded 

 with scholastic rubbish, even then disgusted him, 

 and he afterwards became its declared adversary. 

 That spirit of observation for which he was distin- 

 guished, was early developed. When only nineteen 

 years old, the swinging of a lamp suspended from 

 the ceiling of the cathedral in Pisa, led him to in- 

 vestigate the laws of the oscillation of the pendulum, 

 which he was the first to apply as a measure of time. 

 He left it incomplete, however, and it was brought 

 to perfection by his son Vincenzo, and particularly 

 by Huygens, the latter of whom is to be viewed as 

 the true inventor of the pendulum clock. He 

 studied mathematics under Ostilio Ricci, soon ex- 

 hausted Euclid and Archimedes, and was led, by the 

 works of the latter, in 1586, to the invention of the 

 hydrostatic balance. 



He now devoted his attention exclusively to 

 mathematics and natural science ; and, in 1589, he 

 was made professor of mathematics in the university 

 of Pisa. He was constantly engaged in asserting 

 the laws of nature against a perverted philosophy, 

 for which he is now extolled as the father of modern 

 physics, but then suffered the severest persecutions. 

 In the presence of numerous spectators, he went 

 through with his experiments, which he performed 

 on the tower of the cathedral, to show that weight 

 has no influence on the velocity of falling bodies. 

 By this means he excited the opposition of the ad- 

 herents of Aristotle to such a degree, that, after two 

 years, he was forced to resign his professorship. 

 He retired to the house of Filippo Salviati, where he 

 became acquainted with Francesco Sagredo, a worthy 

 Venetian, upon whose recommendation the senate of 

 Venice, in 1592, appointed him professor of mathe- 

 matics in Padua. He lectured here with un- 

 paralleled success. Scholars from the most distant 

 regions of Europe crowded about him. He delivered 

 his lectures in the Italian language, which he first 

 applied to philosophy. In 1597, he invented his 

 geometrical and military compass. 



The mathematical truths which he discovered 

 after 1602, are highly important ; for example, that 

 the spaces through which a body fells, in equal 

 times, increase as the numbers 1, 3, 5, 7 ; that is, if 

 a body falls 15 Paris feet (about 16 English) in one 

 second, it will fall 45 in two, 75 in three, and so on. 

 Whether the thermometer was his invention it is 

 difficult to determine ; perhaps he only improved it. 

 He made some interesting observations on the 

 magnet. The telescope (q. v.), which, in Holland, 

 remained not only imperfect, but useless, Galileo 

 turned to the heavens, and in a short time made a 

 series of the most important discoveries. He found 



that the moon, like the earth, has au uneven surface ; 

 and he taught his scholars to measure the height of 

 its mountains by their shadow. A particular nebula 

 he resolved into individual stars, and even conjec- 

 tured that the whole Milky Way, with good ins'tru- 

 ments, might be resolved in the same manner. 

 His most remarkable discovery was that of Jupiter's 

 satellites, January 7, 1610. He likewise observed 

 Saturn's ring, though he had not a just idea with 

 regard to it. He saw the sun's spots somewhat 

 later, and inferred, from their regular advance from 

 east to west, the rotation of the sun, and the incli- 

 nation of its axis to the plane of the ecliptic. 

 Scheiner, at Ingoldstadt, aud John Fabricius, preacher 

 in Ostell, in East Friesland, however, have the 

 honour of first publishing tlu's discovery from the 

 press.* 



Galileo's name, meantime, had grown so celebrated 

 that the grand duke Cosmo II., in 1610, appointed 

 him grand ducal mathematician and philosopher, and 

 invited him to become first instructer in mathematics 

 at Pisa, where, however, he was not obliged to 

 reside. He lived sometimes in Florence, and some- 

 times at the country seat Alls Selve, of his friend 

 Salviati. Here he gained a decisive victory for the 

 Copernican system, in 1610, by the discovery of the 

 varying phases of Mercury, Venus, and Mars ; as the 

 motion of these planets about the sun, and their 

 dependence on it for light, were thus established 

 beyond the possibility of doubt. He wrote a work 

 afterwards on the floating and sinking of solid bodies 

 in water, and in this, as well as in all his other 

 writings, he has scattered the seeds of many new 

 doctrines. 



While he was thus employed in enlarging the field 

 of natural philosophy, a tremendous storm was 

 gathering about his own head. He had declared 

 himself in favour of the Copernican system, in his 

 work on the sun's spots, and was therefore denounced 

 as a heretic by his enemies, who thought this theory 

 endangered the honour of the Bible. The monks 

 preached against him, and he went to Rome, where 

 he succeeded hi appeasing his enemies, by declaring 

 that he would maintain his system no further, either 

 by words or writings. He would hardly, however, 

 have escaped the cruelties of the inquisition, unless 

 the grand duke, suspecting his danger, had recalled 

 him. 



In 1618, the appearance of three comets gave him 

 an opportunity to communicate to his friends some 

 general observations on these bodies. His scholar, 

 Mario Guiducci, wrote a work immediately after, in 

 which he severely condemned the Jesuit Grassi. 

 Supposing Galileo to be the author, Grassi attacked 

 him. Galileo replied in his Saggiatore, a master- 

 piece of eloquence, pronounced by Algarotti to be 

 the finest controversial work Italy has ever produced, 

 and, notwithstanding the errors contained in it, a 

 work always worthy to be read. This drew upon 

 him the fury of the Jesuits. 



About this time he completed his famous work, 

 in which, without giving his own opinion, he intro- 

 duces three persons in a dialogue, of whom the first 

 defends the Copernican system, the second the 

 Ptolemaean, and the third weighs the reasons of 

 both in such a way that the subject seems to remain 

 problematical, though it is impossible to mistake the 



* To secure to the Germans the honour of this discovery 

 before the Italians, we only need to compare the date of 

 their works on this subject. The Narratio de Maculis in 

 Sole ob.iervatis of Fabricius appeared in 1611, at Witten- 

 berg ; Scheiner's Tres Epistolai de Maculis solaribus, at 

 Augsburg, in 1612; Galilei's Jstoria e JJimostrattoni 

 intorno alle Macchie safari, first at Rome, in 1613- Lalanda 

 relates the history of the contest for priority, in bis Astro- 

 nomic, iii. p. 386, 2d edition. 



