ASTRONOMY. 



Prag'ue. After residing in this city till 

 the year 1601. he was taken off by a sud- 

 den death, in the midst of his labours, and 

 at an r.ge while he was yet capable of ren- 

 dering great services to astronomy. This 

 great man, as is well known, was the in- 

 ventor of a kind of semi Ptolemaic system 

 of astronomy that was afterwards called 

 by his name, and which he vainly endea- 

 voured to establish, instead of the Coper- 

 nican, or true system. But though he 

 was not happy in this respect, he has 

 been of great use to astronomy, by his 

 numerous observations and discoveries. 



Tycho Brahe, in the latter part of his 

 life, had, for his disciple and assistant, the 

 celebrated Kepler, who was born in 1751, 

 at Wiel, in the duchy of Wirtemberg, 

 and was one of those rare characters that 

 appear in the world only at particular 

 times, to prepare the way for new and 

 important discoveries. Like his master 

 Tycho, he appears to have, attached him- 

 self to the science at a very early age ; 

 and if it be the privilege of genius to 

 change received ideas, and to announce 

 truths which had never before been dis- 

 covered, he may justly be considered as 

 one of the greatest men that had yet ap- 

 peared. Hipparchus, Ptolemy, Tycho 

 Brahe, and even Copernicus himself, 

 were indebted for a great part of their 

 knowledge to the Egyptians, Chaldaeans, 

 and Indians, who were their masters in 

 this science ; but Kepler, by his own ta- 

 lents and industry, has made discoveries, 

 of which no traces are to be found in the 

 annals of antiquity. See BHAHE. 



This great man, after seventeen years 

 of m-. dilation and calculation, having had 

 the idea of comparing them with the 

 powers of the numbers by which they are 

 expressed, he found that the squares of 

 the times of the revolutions of the planets 

 are t<> each other as the cubes of their 

 mean distances from the sun; and that the 

 sani? Kw applies equally to their satel- 

 lites See KEPLER. 



A; he same time also that Kepler, in 

 Germany, was tracing the orbits of the 

 planets* and settling the laws of their mo- 

 tio; Galileo (who was born at Pisa, in 

 Italy. <n 1564) was meditating upon the 

 doctrine of motion in general, and inves- 

 tig;vim- its principles; and from the ad- 

 mirable discoveries which he made in 

 this brunch of the physico-mecnanical 

 sci'-nces, Newton and Huygens were af- 

 tei urds enabled to derive the most 

 bri'iiant and complete theories of all the 

 plane U i \ ni ; ,us. 



About this period, also, a fortunate ac- 

 cident produced the most marvellous in- 



strument that human industry and sags- 

 city could have ever hoped to discover ', 

 and which, by giving a far greater exten- 

 sion and precision to astronomical obser- 

 vations, shewed many irregularities and 

 new phenomena, which had hitherto re- 

 mained unknown. This invention was 

 that of the telescope, which was no soon- 

 er known to Galileo, than he set himself 

 about to improve it ; and the discoveries 

 he was by this means enabled to make 

 were as new as they were surprising. 



The face of the moon appeared full of 

 cavities and asperities, resembling vallies 

 and mountains. The sun, which had 

 generally been considered as a globe of 

 pure fire, was observed to be sullied by 

 a number of dark spots, which appeared 

 on various parts of his surface. A great 

 number of new stars were discovered in 

 every part of the heavens ; the planet 

 Jupiter was found to be attended with 

 four moons, which moved round him in 

 the same manner that our moon moves 

 round the earth; the phases of Venus ap- 

 peared like those of the moon, as had be- 

 fore been concluded by Copernicus, from 

 his theory ; and, in short, most of the ob- 

 servations he made furnished new proofs 

 of the truth of the Copernican system. In 

 publishing the discoveries which he had 

 made with this new instrument, Galileo 

 shewed, in the most incontestible man- 

 ner, the annual and diurnal motion of the 

 earth ; which doctrine, however, was 

 thought so alarming, that it was immedi- 

 ately declared heretical, by a congrega- 

 tion of cardinals, who were assembled 

 upon the occasion ; and its venerable au- 

 thor, one of the most virtuous and en- 

 lightened men of his age, was obliged to 

 abjure, upon his knees, and in the most 

 solemn manner, a truth, which nature and 

 his own understanding had shewn him to 

 be incontrovertible. After this, he was 

 condemned to perpetual imprisonment ; 

 from which, however,, at the end of a 

 year, he was enlarged, by the solicitations 

 of the grand duke'; but that he might not 

 withdraw himself from the power of the 

 inquisition, he was forbid to quit the ter- 

 ritory of Florence, where he died in 

 1642*; carrying with him the regrets of 

 Europe, enlightened by his labours, and 

 their indignation against the odious tri- 

 bunal which had treated him so unwor- 

 thily. See GAMLEO. 



The discoveries of Huygens succeeded 

 thos.- or Keuicr and Gai.ieo and few 

 men have, peiii^ps, men' ed more of the 

 sciences, by the importance and sublimi- 

 ty of his researches. Among other tilings, 

 his happy application of the pendulum to 



