58 SCIENCE IN THE LAST HALF CENTUKY. 



sages of antiquity who for eight centuries, from the time of Thales to 

 that of Galen, toiled at the foundations of physical science. But, with- 

 out entering into the discussion of that large question, it is certain that 

 the labors of these early workers in the field of natural knowledge were 

 brought to a standstill by the decay and disruption of the Roman Em- 

 pire, the consequent disorganization of society, and the diversion of 

 men's thoughts from sublunary matters to the problems of the super- 

 natural world suggested by Christian dogma in the Middle Ages. And, 

 notwithstanding sporadic attempts to recall men to the investigation of 

 nature here and there, it was not until the fifteenth and sixteenth cen- 

 turies that physical science made a new start, founding itself at first 

 altogether upon that which had been done by the Greeks. Indeed, it 

 must be admitted that the men of the Renaissance, though standing on 

 the shoulders of the old philosophers, were a long time before they saw 

 as much as their forerunners had done. 



The first serious attempts to carry further the unfinished work of 

 Archimedes, Hipi)archus, and Ptolemy, of Aristotle and of Galen, 

 naturally enough arose among the astronomers and the physicians. 

 For the imperious necessity of seeking some remedy for the physical 

 ills of life had insured the preservation of more or less of the wisdom 

 of Hippocrates and his successors, and, by a happy conjunction of cir- 

 cumstances, the Jewish and Arabian physicians and philosophers 

 escaped many of the influences which at that time blighted natural 

 knowledge in the Christian world. On the other hand, the supersti- 

 tious hopes and fears which afforded countenance to astrology and to 

 alchemy also sheltered astronomy and the germs of chemistry. 

 Whether for this or for some better reason the founders of the schools 

 of the Middle Ages included astronomy along with geometry, arith- 

 metic, and music as one of the four branches of advanced education, 

 and in this respect it is only just to them to observe that they were far 

 in advance of those who sit in their seats. The schoolmen considered 

 no one to be properly educated unless he were acquainted with — at any 

 rate — one branch of physical science. We have not even yet reached 

 that stage of enlightenment. 



In the early dec ades of the seventeenth century the men of the Re- 

 naissance could show that they had already put out to good interest the 

 treasure bequeathed to them by the Greeks. They had produced the 

 astronomical system of Copernicus, with Kepler's great additions ; the 

 astronomical discoveries and the physical investigations of Galileo ; the 

 mechanics of Stevinus and the "De Magnete" of Gilbert; the anatomy 

 of the great French and Italian schools and the physiology of Harvey. 

 In Italy, which had succeeded Greece in the hegemony of the scientific 

 world, the Accademia dei Lyncei, and sundry other such associations 

 for the investigation of nature, the models of all subsequent academies 

 and scientific societies, had been founded, while the literary skill and 

 biting wit of Galileo had made the great scientific questions of the day 

 not only intelligible, but attractive, to the general public. 



