4 REPORT— 1887. 



such conflict is possible, but that life is governed by chemical and 

 physical forces, even though we cannot in every case explain its phenomena 

 in terms of these forces ; that whether these tend to continue or to end 

 existence depends upon their nature and amount, and that disease and 

 death are as much a consequence of the operation of chemical and 

 physical laws as are health and life. 



Looking back again to our point of departure fifty years ago, let us for 

 a moment glance at Dalton's labours, and compare his views and those of 

 his contemporaries with the ideas which now prevail. In the first place it 

 is well to remember that the keystone of his atomic theory lies not so 

 much in the idea of the existence and the indivisible nature of the 

 particles of matter — though this idea was so firmly implanted in his mind 

 that, being questioned on one occasion on the subject, he said to his friend 

 the late Mr. Ransome, ' Thou knowst it must be so, for no man can split 

 an atom ' — as in the assumption that the weights of these particles are 

 different. Thus whilst each of the ultimate particles of oxygen has the 

 same weight as every other particle of oxygen, and each atom of hydrogen, 

 for example, has the same w^eight as every other particle of hydrogen, the 

 oxygen atom is sixteen times heavier than that of hydrogen, and so on 

 for the atoms of every chemical element, each having its own special 

 weight. It was this discovery of Dalton, together with the further one 

 that the elements combine in the proportions indicated by the relative 

 weights of their atoms or in multiples of these proportions, which at 

 once changed chemistry from a qualitative to a quantitative science, 

 making the old invocation prophetic, ' God created all things according to 

 measure and to weight.' 



The researches of chemists and physicists during the last fifty years 

 have not only strengthened but broadened the foundations of the great 

 Manchester philosopher's discoveries. It is true that his original 

 numbers, obtained by crude and inaccurate methods, have been replaced 

 by more exact figures, but his laws of combination and his atomic 

 explanation of those laws stand as the great bulwarks of our science. 



On the present occasion it is interesting to remember that within a 

 stone's-throw of this place is the small room belonging to our Literary 

 and Philosophical Society which served Dalton as his laboratory. Here 

 with the simplest of all possible apparatus — a few cups, penny ink bottles, 

 rough balances, and self-made thermometers and barometers — Dalton 

 accomplished his great results. Here he patiently worked, marshalling 

 facts to support his great theory, for as an explanation of his laborious 

 experimental investigations the wise old man says : * Having been in my 

 progress so often misled, by taking for granted the results of others, I 

 have determined to write as little as possible but what I can attest by 

 my own experience.' Nor ought we when here assembled to forget that 

 the last three of Dalton's experimental essays — one of which, on a new 

 method of measuring water of crystallisation, contained more than the 

 germ of a great discovery — were communicated to our Chemical Section 



