. TRANSACTIONS OF SECTION B. 565 



least approximate accuracy, and whose places in the periodic system are not dis- 

 puted, twenty -seven agree almost exactly with the actual numbers, whilst nineteen 

 others are not more than one unit astray. 



For a detailed consideration of the conclusions which follow from Dr. Carnelley's 

 views I must refer to his paper as read at our last meeting. Two points bear more 

 ■especially upon the subject now under consideration — that is, if this speculation on 

 the genesis of the elements is well founded. First, the existence of elements of 

 identical atomic weights, isomeric with each other, would be possible ; as such 

 Dr. Carnelley mentions respectively nickel and cobalt (now found to have slightly 

 different atomic weights), rhodium and ruthenium, osmium and iridiiun, and the 

 metals of some of the rare earths. Secondly, in Dr. Carnelley's scheme all the 

 chemical elements save hydrogen are supposed to be composed of two simpler 

 elements, A = 12 and B = — 2. Of these he regards A as a tetrad identical with 

 carbon, and B as a monad of negative weight — perhaps the ethereal fluid of space. 



Dr. Carnelley's three primary elements therefore are carbon, hydrogen, and the 

 «ther. 



Starting from the supposition that pristine matter was once in an intensely 

 heated condition, and that it has reached its present state by a process of free 

 cooling. Dr. E. J. Mills suggests that the elements as we now have them are the 

 result of successive polymerisations. Dr. Mills reminds us that chemical substances 

 in the process of cooling naturally increase in density, and, if such increase be 

 measui-ed as a function of time or of temperature, we sometimes observe that there 

 are critical points corresponding to the formation of new and well-defined sub- 

 stances. In this manner, ordinary phosphorus is converted into the red variety, 

 I is transformed into I,,, So becomes S^, and 'NO., N.^O^. Among organic bodies 

 styrol, in like manner, according to Dr. Mills, is converted into metastyrol, aldehyd 

 into paraldehyd, the cyanates into cyanurates, and turpentine into metatereben- 

 thene. At the critical points above referred to heat is liberated in especial abun- 

 dance, and the bodies thus formed are known as polymers. If wo could gradually 

 cool down substances through a vast range of temperature, we should then pro- 

 bably discover a much greater number of such critical points, or points of multiple 

 proportion, than we have been able to discover experimentally. 



The heat given out in the act of poljTaerisation naturally reverses to some 

 extent the polymerisation itself, and so causes a partial return to the previous con- 

 dition of things. This forward and backward movement, several times repeated, 

 constitutes ' periodicity.' Dr. Mills regards variable stars as instances, now in 

 evidence, of the genesis of elementary bodies. 



From a study of the classification of the elements, Dr. Mills is of opinion that 

 the only known polymers of the primitive matter are arsenic, antimony, and perhaps 

 erbivuH and osmium ; whilst zirconium, ruthenium, samarium, and platinum approxi- 

 mate to the positions of other polymers. Hence, from this genetic view, these 

 elements may be described as products of successive polymerisations. 



I must now call attention to a method of illustrating the periodic law, proposed 

 ty my friend Professor Emerson Eeynolds, of the University of Dublin, which will 

 here assist us. Professor Reynolds points out that in each period the general pro- 

 perties of the elements vary from one to another with approximate regularity 

 tmtil we reach the seventh member, which is in more or less striking contrast with 

 the first element of the same period, as well as with the first of the next. Thus 

 chlorine, the seventh member of Mendeleeff's third period, contrasts sharply 

 both with sodium, the first member of the same series, and with potassium, 

 the first member of the next series; whilst, on the other hand, sodium 

 and potassium are closely analogous. The six elements whose atomic weights 

 intervene between sodium and potassium vary in properties, step by step, until 

 chlorine, the contrast to sodium, is reached. But from chlorine to potassium, the 

 analogue of sodium, there is a change in properties per saltum. Further, such 

 alternations of gradual and abrupt transitions are observed as the atomic weights 

 increase. If we thus recognise a contrast in properties — more or less decided — 



