TEANSACTIONS OF SECTION B. 627 



and end-all of science; that all differences are merely quantitative ; that there is no 

 such thing as mere quality. The whole philosophy of our age is expressed in this 

 one proposition : All differences ■within the sphere of our experience are quanti- 

 tative. It is the basis of Darwinism, if I am not mistaken, and underlies many of 

 our political and social theories. Of course it is a mere assumption if stated 

 generally, for the phenomena that admit of purely quantitative expression are few 

 in number compared with those that do not ; but then it is surmised, and with some 

 degree of probability, that the vast region outside the quantitative sphere will in 

 time come to be included within it. The past history of science seems to render 

 this likely in the future. The science of chemistry has so far, however, presented 

 an insuperable barrier to the general adoption of this view, and will continue to do 

 so as long as the so-called elements remain what we now admit them to be — in- 

 destructible, immutable, inconvertible. It is possible to denote all the known pro- 

 perties of gold and silver, their atomic weight, specific gi-avity, hardness, malleability, 

 action towards heat, light, and electricity in precise numbers with reference in each 

 case to a certain standard, and yet we cannot say that silver minus a little of this, 

 plus a little of that, constitutes gold — the two elements are essentially and radically 

 distinct. Unless we admit with the alchemists that by taking away a little of A 

 and adding a little of B we can convert one metal into another, one element into 

 another, the quantitative method must fall short of its complete development in 

 chemistry. Numerous attempts have, therefore, been made to show the theoretical 

 probabilit}^, even if it should not be possible to prove it experimentally, of the so- 

 called elements being really compound bodies, or at least of their containing a 

 basic matter common to all. My predecessor in this chah" has endeavoured to show 

 in the brilliant address delivered to this Section on the occasion of the last meeting 

 of the Association that the barrier hitherto presented to us by the intractability of 

 our present elements may be overcome, and has adduced experimental illustrations 

 in favour of his view of the compound nature of the elements. Mr. Crookes has 

 called to his aid the doctrine of evolution, which has proved so valuable an instru- 

 ment in the hands of the biologist, maintaining that the elements, like the species 

 of plants and animals, were gradually evolved by some process of condensation 

 from a primordial matter called by him ' protyle,' each step in the process being 

 represented by a distinct element. This is doubtless taking very safe groimd, for if 

 the process of evolution was the same in the inorganic as it is supposed to have 

 been in the organic world, the process can never be repeated, and we shall, there- 

 fore, never be in a position to illustrate it experimentally. I may, however, have 

 misunderstood what Mr. Crookes meant to convey, and, if so, must apologise for 

 misrepresenting his views. Granting, however, the possibility of our resolving our 

 present elements, were it in theory only, into modifications of one basic material 

 out of which they have been evolved, the question would still remain to be 

 answered. What has caused this primordial matter to be split up into groups and 

 forms having distinct and opposite qualities ? and when this question is answered, 

 if it can be answered even in a problematical way, then other questions would 

 arise, imtil by degrees we should arrive at the confines of physical knowledge and 

 find ourselves in the region of metaphysics, where scientific reasoning ceases and 

 thinking for scientific purposes becomes unprofitable. Excursions into this region 

 would indeed be very useful if on returning to physical regions we could every time 

 bring back with us an instrument as potent and far-reaching as the atomic theory 

 has proved to be, a theory which still remains the basis of all our reasoning in 

 chemistry, but then the atomic theory has been quite an exceptional instance. 

 Metaphysical speculation, such as the Naturphilosophie of the Germans has dealt 

 in, has, generally speaking, been utterly barren in natural science. 



I will not on the present occasion dwell on the vast addition made to the 

 number of useful and beautiful substances by chemists during the last fifty years. 

 Their number is legion, and their mere description fills volumes, whereas half a 

 century ago a dictionary of moderate size would have sufiieed for the purpose. 

 Among these newly discovered substances none are more remarkable than the 

 metals rubidium, caesium, thallium, indium, gallium, the existence of which was 

 revealed by the spectroscope, and which, indeed, would probably have remained 



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