TRANSACTIONS OF SECTION B. 561 



development ■which we recognise in the univeree run alono- certain fixed lines which 

 have been preconceived and foreordained. To the careless and hasty eye design 

 and evolution seem antagonistic ; the more careful inquirer sees that evolution, 

 steadily proceeding along an ascending scale of excellence, is the strongest argu- 

 ment in favour of a preconceived plan. 



The array of the elements cannot fail to remind us of the general aspect of the 

 organic world. In hoth cases we see certain groups well filled up, even crowded, 

 with forms having among themselves but little specific difference. On the other 

 hand, ia both, other forms stand widely isolated. Both disjilay species that are 

 common and species that are rare ; both have groups widely distributed — it might 

 be said cosmopolitan— and other gi'oups of very restricted occurrence. Among 

 animals I may mention as instances the Monotremata of Australia and New 

 Guinea, and among the elements the metals of the so-called rare earths. 



Now, as these facts in the distribution of organic forms are generally considered 

 lay biological experts to rank among the weightiest evidences in favour of the origin 

 of species by a process of evolution, it seems natural, in this case as in the other, 

 to view existing elements not as primordial but as the gradual outcome of a process 

 of development, possibly even of a ' struggle for existence.' Bodies not in harmony 

 with the present general conditions have disappeared, or perhaps have never 

 existed. Others— the asteroids among the elements — have come into being, and 

 have survived, but only on a limited scale ; whilst a third class are abundant 

 because surroimding conditions have been favoui-able to their formation and 

 preservation. 



The analogy here suggested between elements and organisms is, indeed, not the 

 closest, and must not be pushed too far. Fi'om the nature of the case there cannot 

 occur in the elements a difference corresponding to the difference between living 

 and fossil organic forms. The ' great stone book ' can tell us nothing of extinct 

 elements. Nor would I for a moment suggest that any one of our present elements, 

 however rare, is like a rare animal or plant in process of extinction ; that any new 

 element is in the course of formation, or that the properties of existing elements are 

 gradually undergoing modification. All such changes must have been confined to 

 that period so remote as not to be grasped by the imagination, when our Earth, or 

 rather the matter of which it consists, was in a state very different from its present 

 condition. The epoch of elemental development is decidedly over, and I may 

 observe that in the opinion of not a few biologists the epoch of organic development 

 is verging upon its close. 



Making, however, every allowance for these distinctions, if evolution be a 

 cosmic law, manifest in heavenly bodies, in organic individuals, and in organic 

 species, we shall in all probability recognise it, though under especial aspects, in 

 tliose elements of which stars and organisms are in the last resort composed. 



Is there, then, in the first place, any direct evidence of the transmutation of 

 any supposed 'element' of our existing list into another, or of its resolution into 

 anything simpler ? 



To this question I am obliged to reply in the negative. 



I doubt whether any chemist here present could suggest a process which would 

 hold out a reasonable prospect of dissociating any of our accepted simple bodies. 

 The highest temperatures and the most powerful electric currents at our disposal 

 have been tried, and tried in vain. At one time there seemed a possibility at least 

 that the interesting researches of Prof. Victor jMeyer might show tiie two higher 

 members of the halogen group, bromine and iodine, as entering upon the path of 

 dissociation. These hopes have not been fulfilled. It maj' be said, in the general 

 opinion of the most eminent and judicious chemists, that none of the phenomena 

 thus elicited prove that even an approach has been made to the object in view. 



Even if we leave our artificial laboratories and seek an escape from the diffi- 

 culty by observing the processes of the great laboratories of Nature, we feel no 

 sufficiently firm ground. 



We find ourselves thus driven to indirect evidence — to that which we may 

 glean from the mutual relations of the elementary bodies. Such evidence of great 

 value is by no means lacking, and to this I now beg to direct attention. First, we 



1886. 



