PRESIDENTS ADDRESS—-SECTION A. 25 
(g) motion being understood in the ordinary sense (sec. 24, 
p- 32). Descartes’ explanation of the mechanism of Nature is, 
however, at least as truly atomistic as, say, either Lord Kelvin’s, 
Dr. Burton’s, or Mr. Larmor’s, whose views are hereinafter more 
fully referred to, and, excepting mere form, is substantially 
identical with that of any physicist who believes the material 
atom to be constituted by conditions imposed upon elements of 
a supersensible ether. Descartes may be looked upon as the 
founder cf that form of atomism, if indeed it was not fundamen- 
tally the notion which Aristotle had twenty centuries earlier. 
The difference between Aristotle’s ‘t\7” and Descartes’ “ Ex- 
tended Substance” is not by any means well marked. 
14. Newton.—That Newton accepted the atomic doctrine is 
disclosed in his somewhat curious assertion :—‘* God made atoms 
of such sizes and figures, and with such other properties, and in 
such proportion to space as most conduced to the end for which 
he formed them’—a statement at least as guarded as it is 
dogmatic. 
15. Hooke, and the Suggestion of the Kinetic Theory of Gases. 
—An important application of the atomic doctrine, and one of 
first fruits of Boyle’s espousal thereof, was the application, as 
early as 1676, of the notion of atomic impact as the cause of the 
pressure of a gas. This explanation was indicated by Robert 
Hooke (£), Boyle’s protegé, and is a remarkable example of 
Hooke’s penetration in physical matters (/). 
16. Swedenborg’s Theories of Atoms and Molecules.—In 1721 
Swedenborg (m) published his Prodromus principiorum rerum 
naturalium, containing a theory of the genesis of different kinds 
of matter. He entered into elaborate calculations concerning 
the sizes, shapes, and proportions to space of particles formed 
from atoms, the latter being, according to him, geometrical 
points, from which, however, are formed hollow spheres all of 
the same nature, but differing as to size. These hollow spheres 
are the fundamental elements of all kinds of matter, the pro- 
perties of which depend upon the size and special arrangement 
of the component spheres. The molecular structure deduced for 
water from forty-seven experiments and observations made with 
that liquid, was a large hollow sphere at each angle of a cube, 
the eigit large spheres being surrounded by smaller spheres ; 
these again by smaller, and so on through a series of six down 
to the geometrical point! Fifty experiments on common salt 
gave particles shaped like cubes or tetrahedra, but with curved 
sides. The whole scheme of explanation appears fanciful. 
17. Boscovich’s Centres of Force—In 1758 appeared the 
famous treatise of Boscovich (m), on the molecular theory of 
k) [1635 - 1703] (m) [1688 -1772]. 
(1) Lectures de potentia restitutiva, or of Spring. (n) [1711—1787. ] 
