THE ASTRONOMICAL VIEW OF NATURE. 351 



the latter in stable and self-repeating averages. Pos- 

 sessed therefore, as we seem to be, of the greatest wealth 

 and variety of observations and notions, we may perhaps 

 erroneously conclude that we can grasp the simpler 

 cosmical and molecular movements and phenomena by 

 starting from molar, physical, or mechanical models. 1 



1 English naturalists have always 

 excelled in this line of investigation, 

 whereas foreign scientific literature 

 has been rich in purely mathemati- 

 cal deductions from formulae which 

 contained no construirbare Vorstel- 

 lung. And it is interesting to note 

 that both lines of thought go back 

 to Newton. Whereas Newton him- 

 self believed in the possibility of a 

 mechanical explanation or represen- 

 tation of the gravitation formula, 

 the second edition of the ' Prin- 

 cipia ' by Cotes can be looked upon 

 as sanctioning the view that gravi- 

 tation is an ultimate quality which 

 must be accepted as such ; and as 

 it was the second edition through 

 which Newton's ideas became large- 

 ly known on the Continent, it is 

 not surprising that he was there 

 accused of reintroducing the quali- 

 tates occultce of the older metaphys- 

 ics, which Descartes and others had 

 successfully banished. Clerk Max- 

 well says (" Action at a Distance," 

 'Scient. Pap.,' vol. ii. p. 316): 

 " The doctrine of direct action at 

 a distance cannot claim for its 

 author the discoverer of universal 

 gravitation. It was first asserted 

 by Roger Cotes in his preface to 

 the ' Principia,' which he edited 

 during Newton's life. According 

 to Cotes it is by experience that 

 we learn that all bodies gravitate. 

 We do not learn in any other way 

 that they are extended, movable, 

 or solid. Gravitation, therefore, 

 has as much right to be considered 

 an essential property of matter as 

 extension, mobility, or impenetra- 



bility. And when the Newtonian 

 philosophy gained ground in Europe, 

 it was the opinion of Cotes rather 

 than that of Newton that became 

 most prevalent." In fact, philoso- 

 phers could be divided into two 

 classes those who took the fact 

 of gravity or the wider idea of a 

 universal attraction as a beginning, 

 and drew from this beginning all 

 the possible mathematical and ex- 

 perimental consequences which they 

 could think of ; and those who, 

 whilst admitting this process as a 

 legitimate one, thought it neces- 

 sary to go behind the assumed 

 beginning and find a still more 

 hidden mechanical reason for this 

 admitted property. To the latter 

 class belonged Newton himself, 

 Huygens, Euler, and in modern 

 times notably Faraday and his fol- 

 lowers ; to the former class be- 

 longed Daniel Bernoulli, who wrote 

 to Euler, 4th February 1744, refer- 

 ring to the ether theory of the lat- 

 ter : " Moreover, I believe both that 

 the ether is gravis versus solcm and 

 the air versus terram, and I cannot 

 conceal from you that on these 

 points I am a perfect Newtonian, 

 and I am surprised that you ad- 

 here so long to the principiis Car- 

 tcsianis ; there is possibly some feel- 

 ing in the matter. If God has been 

 able to create an animam whose na- 

 ture is unknown to us, He has also 

 been able to impress an attractionem 

 universalem materue, though such is 

 attractio supra captum, whereas the 

 principia C'artcsiana involve always 

 something contra captum " (see 



