26 PRESIDENTIAL ADDRESS. — SECTION' II. 



species of the two or three milhons now inhabiting the earth had been estab- 

 lished solely, or mainly, by the operation of natural selection."* 



It is most obvious all round, then, — and this has a far wider 

 application than merely to the sciences of our own section, — that 

 theories which were looked upon as quite indisputable considerably 

 less than a century ago, have since then been fundamentally altered. 

 We, too, may rest assured that, notwithstanding all the dogmatism 

 wherewith we maj- proclaim our newly acquired scientific beliefs, 

 the foundations also of these beliefs will yet be subjected to a good 

 deal of disintegration, and it is remarkable that in the past, just 

 when some theories have been taken as most positively established, 

 they have, all of a sudden, been completely dissipated at the advent 

 of fuller knowledge. All this should make abundantly evident the 

 folly of attempting to square the transcendental with the limited 

 knowledge and ephemeral notions which we may happen to possess 

 at any one particular instant. 



Since Charles Darwin's day the scope of the Evolution hypothesis 

 has been widened considerably ; indeed. Dr. A. R. Wallace is 

 reported to have said that " Darwin must have turned in his 

 grave more than once if any echoes of ' Darwinism ' ever reached 

 him there. "t j\Iany — perhaps most ordinary men — when speaking 

 of evolution, limit their ideas to the organic world — animal and 

 vegetable — that is to say, to genetic development : but numbers 

 of others would throw back the process to a very much earlier 

 date, and accordingly there has been of late a good deal of talk 

 about " Inorganic Evolution," and especially about that phase 

 thereof which is now generally referred to by the expression. " The 

 evolution of the elements." This evohition, Mr. Soddy tells us, 

 " is actually proceeding under our eyes."t What we see. however, 

 is not evolution but dissolution ; dissolution, which Spencer 

 declared to be " the counter-change which, sooner or later, every 

 evolved aggregate tmdergoes."§ The recently-discovered trans- 

 mutation of radium into helium, which is typical of the kind of 

 chemical evolution whereof we are speaking, proceeds, as we all 

 know, and as Mr. Soddy himself admits, " from the complex to 

 the simple " ; to call this evolution is not only to deal a deadly 

 blow at Spencer's celebrated " formula," but such an addition 

 to the already multiform use of the word evolution cannot be 

 less disastrous to a right understanding of the order of nature 

 than failure to discriminate between addition and subtraction or 

 between multiplication and division would be to all mathematical 

 accuracy. 



I must, however, turn from the temptation to discuss trans- 

 cendental and theoretical problems to the consideration of matters 

 more common-place, namely, some of the practical questions tli^t 

 have demanded the attention of chemists in South Africa of late, 

 and are likely to continue doing so — possibly with increased 



* " International Quarterly," Dec. -Mar., 1902-3. 



t See " Pall Mall Magazine," Sept., 1904, p. 74. 



t " The Evolution of the Elements," Brit. Assoc. Report. 1906, York, 



126. 



§ " Essays," ^'ol. 2, p. 142. 



