August 25, 1905.] 



SCIENCE. 



239 



pier, away on his Scottish estates, invented 

 logarithms; and Horrocks, in the seclusion 

 of a Lancashire curacy, was the first to ob- 

 serve a transit of Venus. But for more 

 than half a century the growth of physical 

 science was mainly due to M^orkers on the 

 continent of Europe. Galileo was making 

 discoveries in the mechanics of solids and 

 fluids, and, specially, he was building on a 

 firm foundation the fabric of the system of 

 astronomy, hazarded nearly a century be- 

 fore by Copernicus ; he still was to furnish, 

 by bitter experience, one of the most strik- 

 ing examples in the history of the world 

 that truth is stronger, than dogma. Kepler 

 was gradually elucidating the laws of 

 planetary motion, of which such significant 

 use was made later by Newton; and Des- 

 cartes, by his creation of analytical geome- 

 try, was yet to effect such a constructive 

 revolution in mathematics that he might 

 not unfairly be called the founder of 

 modern mathematics. In England the 

 times were out of scientific joint: the 

 political distractions of the Stuart troubles, 

 and the narrow theological bitterness of the 

 commonwealth, made a poor atmosphere for 

 the progress of scientific learning, which 

 was confined almost to a faithful few. The 

 fidelity of those few, however, had its 

 reward; it was owing to their steady con- 

 fidence and to their initiative that the Royal 

 Society of London was founded in 1662 by 

 Charles II. At that epoch, science (to 

 quote the words of a picturesque historian) 

 became the fashion of the day. Great 

 Britain began to contribute at least her 

 fitting share to the growing knowledge of 

 nature; and her scientific activity in the 

 closing part of the seventeenth century 

 was a realization, wonderful and practical, 

 of a part of Bacon's dream. Undoubtedly 

 the most striking contribution made in that 

 period is Newton's theory of gravitation, 

 as expounded in his ' Principia,' published 

 in 1687. 



That century also saw the discovery of 

 the fluxional calculus by Newton, and of 

 the differential calculus by Leibnitz. 

 These discoveries provided the material for 

 one of the longest and most deadening con- 

 troversies as to priority in all the long his- 

 tory of those tediously barren occupations ; 

 unfortunately they are dear to minds which 

 cannot understand that a discovery should 

 be used, developed, amplified, but should 

 not be a cause of envy, quarrel, or contro- 

 versy. Let me say, incidentally, that the 

 controversy had a malign influence upon 

 the study of mathematics as pursued in 

 England. 



Also, the undulatory theory of light 

 found its first systematic, if incomplete, 

 exposition in the work of Huygens before 

 the century was out. But Newton had an 

 emission theory of his own, and so the un- 

 dulatory theory of Huygens found no favor 

 in England until rather more than a hun- 

 dred years later ; the researches of Thomas 

 Young established it on a firm foundation. 



Having thus noted some part of the stir 

 in scientific life which marked the late years 

 of the seventeenth century, let me pass to 

 the second of our centenaries: it belongs 

 to the name of Edmond Halley. Quite in- 

 dependently of his achievement connected 

 with the year 1705 to which. I am about to 

 refer, there are special reasons for honor- 

 ing Halley 's name in this section at our 

 meeting in South Africa. When a young 

 man of twenty-one he left England for St. 

 Helena, and there, in the years 1676-1678, 

 he laid the foundations of stellar astronomy 

 for the southern hemisphere; moreover, in 

 the course of his work he there succeeded 

 in securing the first complete observation 

 of a transit of Mercury. After his return 

 to England, the next few years of his life 

 were spent in laying science under a special 

 debt that can hardly be over-appreciated. 

 He placed himself in personal relation with 

 Newton, propounded to him questions and 



