778 



SCIENCE. 



[N. S. Vol. V. No. 125. 



back upon Hipparclius and Ptolemy as the 

 earliest ancestors of whom he has positive 

 knowledge. He can trace his scientific de- 

 scent from generation to generation, through 

 the periods of Arabian and medifeval 

 science, through Copernicus, Kepler, New- 

 ton, La Place and Herschel, down to the 

 present time. The evolution of astronom- 

 ical knowledge, generally slow and gradual, 

 offering little to excite the attention of the 

 public, has yet been marked by two cata- 

 clysms. One of these is seen in the gi-and 

 conception of Copernicus that this earth on 

 which we dwell is not a globe fixed in the 

 center of the universe, but is simply one of 

 a number of bodies, turning on their own 

 axes and at the same time moving around 

 the sun as a center. It has always seemed 

 to me that the real significance of the 

 heliocentric system lies in the greatness of 

 this conception rather than in the fact of 

 the discovery itself. There is no figure in 

 astronomical history which may more ap- 

 propriately claim the admiration of man- 

 kind through all time than that of Coper- 

 nicus. Scarcely any great work was ever so 

 exclusively the work of one man as was the 

 heliocentric system the work of the retiring 

 sage of Frauenburg. No more striking 

 contrast between the views of scientific re- 

 search entertained in his time and in ours 

 can be seen than that seen in the fact that, 

 instead of claiming credit for his great work, 

 he deemed it rather necessary to apologize 

 for it and, so far as possible, to attribute his 

 ideas to the ancients. 



A century and a half after Copernicus 

 followed the second great step, that taken 

 by Newton. This was nothing less than 

 showing that the seemingly complicated 

 and inexplicable motions of the heavenly 

 bodies were only special cases of the same 

 kind of motion, governed by the same 

 forces, that we see around us whenever a 

 stone is thrown by the hand or an apple 

 falls to the ground. The actual motions of 



the heavens and the laws which govern 

 them being known, man had the key with 

 which he might commence to unlock the 

 mysteries of the universe. 



When Huyghens, in 1656, published his 

 Systema Saturnium, where he first set forth 

 the mystery of the rings of Saturn, which, 

 for nearly half a century, had perplexed 

 telescopic observers, he prefaced it with a 

 remark that many, even among the learned, 

 might condemn his course in devoting so 

 much time and attention to matters far out- 

 side the Earth, when he might better be 

 studying subjects of more concern to hu- 

 manity. Notwithstanding that the inventor 

 of the pendulum clock was, perhaps, the last 

 astronomer against whom a neglect of 

 things terrestrial could be charged, he 

 thought it necessary to enter into an elabo- 

 rate defense of his course in studying the 

 heavens. Now, however, the more distant 

 objects are in space — -I might almost add 

 the more distant events are in time— 

 the more they excite the attention of 

 the astronomer, if only he can hope to 

 acquire positive knowledge about them. 

 Not, however, because he is more interested 

 in things distant than in things near, but 

 because thus he may more completely em- 

 brace in the scope of his work the begin- 

 ning and the end, the boundaries of all 

 things, and thus, indirectly, more fully 

 comprehend all that they include. From 

 his standpoint 



"All are but parts of one stupendous whole, 

 Whose body nature is and God the soul." 



Others study nature and her plans as we 

 see them developed on the surface of this 

 little planet which we inhabit ; the astrono- 

 mer would fain learn the plan on which the 

 whole universe is constructed. The mag- 

 nificent conception of Copernicus is, for 

 him, only an introduction to the yet more 

 magnificent conception of infinite space con- 

 taining a collection of bodies which we call 



