94 THE POPULAR SCIENCE MONTHLY. 



be realized in thought, whatever ground there may be for dissenting 

 from the opinion of Sir W. Hamilton (" Lectures on Metaphysics," 

 Boston edition, p. 385), that "we cannot represent extension to the 

 mind except as colored." 



Thus the solid, tangible reality, craved by Prof. Tyndall's " scien- 

 tific imagination," wholly vanishes from the " seeking intellect " the 

 moment this intellect attempts to grasp it apart from the notion which 

 is said to presuppose it as its necessary substratum. If the deliver- 

 ances of the scientific imagination are authoritative in science, the no- 

 tion of the primordial atom must be relegated to the regions beyond 

 the bounds of scientific thought. 



There is another and very obtrusive aspect of the atomic theory in 

 which its utter inability to satisfy the demands of the " scientific im- 

 agination " has long since been recognized. As I have already shown, 

 the atomic theory, in whatever form it is held, presupposes the separa- 

 tion of the atoms by void, interstitial spaces. The only difference of 

 opinion respecting these spaces is as to their magnitude, the emergen- 

 cies of the modern theories of heat and light having led to the suppo- 

 sition that even in the case of the purely hypothetical " ether " (which 

 is nothing but a clothes-horse for all the insoluble difficulties presented 

 by the phenomena of sensible material existence — a fagot of occult 

 qualities and principia expressiva, whose role in the material world at 

 large is analogous to the part formerly played by the aura vitalis, 

 and similar phantasms, in the organic world) the interspaces are 

 very great in comparison with the dimensions of the atoms, so that a 

 group of these atoms is not infrequently compared with a stellar or 

 planetary system. Nevertheless, their motions are construed as effects 

 of their mutual attractions and repulsions. But how is the mutual 

 action of atoms existing by themselves in complete insulation and 

 wholly without contact to be realized in* thought ? We are here in 

 the presence of the old difficulties respecting the possibility of actio 

 in distans which presented themselves to the minds of the physicists 

 in Newton's time, and constituted one of the topics of the famous dis- 

 cussion between Leibnitz and Clarke, in the course of which Clarke 

 made the remarkable admission (Fourth Letter of Clarke, § 45, "Leib- 

 nitii Opera," ed. Erdmann, p. 762) that, " if one body attracted an- 

 other without an intervening body, that would be, not a miracle, but 

 a contradiction ; for it would be to suppose that a body acts where it 

 is not " — otherwise expressed : inasmuch as action is but a mode of 

 being, the assertion that a body can act where it is not would be tanta- 

 mount to the assertion that a body can be where it is not. This ad- 

 mission was entirely in consonance with Newton's own opinion ; in- 

 deed, Clarke's words are but a paraphrase of the celebrated passage in 

 one of Newton's letters to Bentley, cited by John Stuart Mill in his 

 " System of Logic," which runs as follows : 



" It is inconceivable that inanimate brute matter should, without 



