THE BELFAST ADDRESS. 463 
is bruin-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 Ete"riial, 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 Q\\Q 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 Dalton to confer upon it an entirely new 
significance. In our day there are secessions from the 
theory, but it still stands firm. Loschmidt, 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 
