Section I.— ASTRONOMY, MATHEMATICS. PHYSICS, 

 METEOROLOGY, GEODESY, SURVEYING, ENGINEER- 

 ING, ARCHITECTURE AND GEOGRAPHY. 



President of the Section : — Professor W. A. D. Rudge, M.A. 



MONDAY, SEPTEMBER 27. 



The President delivered the following address : — 

 THE GENESIS OF MATTER. 



From the very earliest times speculation has been rife as to the 

 natme of matter. Thales, B.C. 600, held that everything was 

 composed of water — Heraclitus thought that air and tire were the 

 elements from which everything could be elaborated, while 

 Empedocles and Aristotle considered that all might be regarded 

 as being compounded of earth, water, fire and air ; but these four 

 they seemed to have looked upon as modifications of one primary 

 kind of matter. That it was possible for one kind of matter to 

 pass into another kind of matter seems to have been accepted as 

 a truism. Aristotle himself considered that the four elements were 

 not sufficient, and he therefore assumed the existence of a fifth, 

 which he called " ousia." and this — analagous to our ether — 

 permeated everything. 



It was Lucretius who first gave us the definite idea of matter 

 being built up of the small particles which we now call " atoms." 

 He says, in " De Rerum Natura " : 



" For inlinite atoms in a boundless void 

 By endless motion build the frame of things." 



The venerable Bede refers to small divisions of time under the 

 name of " atomi," so that the idea of ultimate particles was 

 probably well understood at a very early date. 



During the Middle Ages the work of the alchemists was largely 

 devoted to endeavours to transmute one kind of matter — i.e., 

 atoms — into another, for at this time the modern chemical theory 

 of the immutability of the atom had not been conceived. Very 

 little was done by the alchemists to advance our real knowledge 

 of matter, and its inner structure troubled them not at all. 



Robert Boyle advanced a theory that all substances were com- 

 posed of minute particles and that combination took place between 

 these particles, rather than between the masses as a whole, taking 

 part in a chemical change. But it was Dalton who first definitely 

 put the question of the atomic structure of matter upon a firm 

 foundation, showing that there were many difterent kinds of atoms, 

 and that to each atom might be assigned a definite, relative weight. 

 These relative weights have been regarded as one of the most 

 important of the chemical properties associated with the atom, 

 for Dalton showed that chemical union occurred between definite 

 proportions by weight. Consequently the efforts of chemists have 

 been from that time devoted to the determination of the value 



