TRAIS'SACTIONS OF SECTION G. 857 



Still better data on whicli to reason, they yet continued to ascribe, as the very names 

 of the planets indicate, connections between them and the g-ods. 



The outcome, however, of the teaching of the Greek schools, culminating as it 

 did in the splendid worli of the Alexandrian philosophers, resulted in the mistaken 

 formula that the earth was the centre around which all the phenomena of nature 

 were carried on. 



It must not be imagined for one moment that Hipparchus and Ptolemy were 

 not acute and accurate observers. They at an early period detected some of those 

 inequalities in the moon's motion which require all the force of the gravitation 

 theory to explain. 



They defined, by patient observation, the irregular motions of the planets, 

 sometimes progressing, sometimes retrograding, and with wonderful accuracy they 

 were able to measure the precession of the equinoxes which carries the equinoctial 

 points backwards along the line of the ecliptic. 



They had a very clear conception of the rotundity of the earth, as we know 

 from the fact that they made attempts to measure an arc of meridian. 



All this wonderful mass of observation and discovery, when taking into con- 

 sideration the imperfect means at their disposal, will ever remain throughout all 

 ages one of the greatest monuments to perpetuate the fame of the men who pro- 

 duced it. 



The question at once arises, How was it that with their wonderfully accurate 

 observations and their perfect knowledge of the movements of the heavenly bodies 

 they did not arrive at some of those revelations which later ages have brought to 

 light? 



It is difficult to answer this question with any degree of precision, but one can 

 see clearly that their minds were governed, and the results of their inductions 

 vitiated, by conceptions such as those of which I have above spoken. 



These conceptions were that, seeing that the sun, moon, and planets appeared 

 to revolve around the earth and return at dlfi'erent periods into closed orbits, 

 therefore, as a circle was the most perfect of all figures, they must necessarily 

 revolve in circular orbits, and that as celestial bodies this motion must be 

 uniform 



Consequently, to unite together the accurate observations that they had made 

 of all the varying motions of the heavenly bodies, they had to invent circular 

 orbits and smaller orbits carried by these in which the sun and planets revolved, 

 and so gradually built up that wonderful and complex system, to which the name 

 of Ptolemy is always attached, of cycles, epicycles, and deferents, by which in a 

 most complicated manner they were able at length to reconcile their accurate 

 observations with their preconceived idea of circular motion. The Ptolemaic 

 system will always remain a wonderful monument to the skill of the observers and 

 the acuteness of the thinkers in the ancient world. 



Turning now to the domain of mechanics, with which were intimately bound up 

 their ideas of geometry, we find, as our old friend Euclid has long since taught us, 

 not only that they were among the most acute reasoners, but that they possessed 

 logic, which, when applied to such conceptions as these, has remained after 2,000 

 years the text-book in our schools. 



But in their estimate of the uses of geometry and the functions of the conic 

 sections, the philosophers of old regarded them mainly as a species of intellectual 

 athletics by which the mind was trained and perfected, and they believed that it 

 was degradation to apply that knowledge to the affairs of mundane life. 



In the case of Archimedes we see the master-mind grappling for the first time 

 with some of the great problems of mass and of force, and solving to a large extent 

 some of the principal problems placed before him. 



But here also Greek notions of mass and of force were mixed up with others, 

 which ascribe to them properties perfectly ideal, and it was considered, in the 

 words of our great poet, that the application of these wonderful discoveries to 

 the affairs of life was ' base mechanical.' 



No doubt much of this was due to the fact that the teachings of the old Greeks 

 were held to be exclusively the property of certain schools and academies, and that 



