THE BELFAST ADDRESS. 463 



is brain-disease; but then the immortal reason sits apart, 

 and cannot be touched by the disease. The errors of mad- 

 ness are those of the instrument, not of the performer. 



It may be more than a mere result of education, con- 

 necting itself, probably, with the deeper mental structure 

 of the two men, that the idea of Gasseudi, above enunciated, 

 is substantially the same as that expressed by Professor 

 Clerk Maxwell, at the close of the very able lecture deliv- 

 ered by him at Bradford in 1873. According to both phi- 

 losophers, the atoms, if I understand aright, are prepared 

 materials, which, formed once for all by the Eternal, pro- 

 duce by their subsequent interaction all the phenomena of 

 the material world. There seems to be this difference, 

 however, between Gassendi and Maxwell. The one postu- 

 lates, the other infers his first cause. In his " manu- 

 factured articles," as he calls the atoms, Professor Maxwell 

 finds the basis of an induction, which enables him to scale 

 philosophic heights considered inaccessible by Kant, and 

 to take the logical step from the atoms to their Maker. 



Accepting here the leadership of Kant, I doubt the 

 legitimacy of Maxwell's logic; but it is impossible not to 

 feel the ethic glow with which his lecture concludes. 

 There is, moreover, a very noble strain of eloquence in his 

 description of the steadfastness of the atoms: " Natural 

 causes, as we know, are at work, which tend to modify, if 

 they do not at length destroy, all the arrangements and 

 dimensions of the earth and the whole solar system. But 

 though in the course of ages catastrophes have occurred 

 and may yet occur in the heavens, though ancient systems 

 may be dissolved and new systems evolved out of their 

 ruins, the molecules out of which these systems are built 

 the foundation stones of the material universe remain 

 unbroken and unworn." 



The atomic doctrine, in whole or in part, was entertained 

 by Bacon, Descartes, Hobbes, Locke, Newton, Boyle, and 

 their successors, until the chemical law of multiple pro- 

 portions enabled Daltcn to confer upon it an entirely new 

 significance. In our day there are secessions from the 

 theory, but it still stands firm. Loschrnidt, Stoney, and 

 Sir William Thomson have sought to determine the sizes 

 of the atoms, or rather to fix the limits between which 

 their sizes lie; while the discourses of Williamson and Max- 

 well delivered in Bradford in 1873 illustrate the present 



