18 JOURNAL OF THE 
against. Atany rate all hypothetical talk about strong bonds, 
and weak bonds, double bonds and triple is to be avoided? 
If then valetice varies, can it be an inherent property of the 
unchanging atoms? Experiments have shown that it varies 
with the nature of the combining element, that it varies with 
the temperature and with other conditions. It is not depend- 
ent upon the atomic weight in the same sense as other prop- 
erties are dependent upon it. ‘Thus in the same group the 
valence remains the same whether the atoms weigh nine times 
as much as hydrogen or two hundred times as much. 
We seem shut up to the conclusion that valence is not one 
of the primitive inherent properties of the atom but is rela 
tive, It is rather to be regarded as the resultant of the mutu- 
al influence of the atoms of the combining elements, The 
clear grasping of this idea is an importhant step forward. 
Unfortunately the distinction is not always made nor consist- 
ently adhered to. 
It may not be amiss to cite here the utterance of Lothar 
Meyer in regard to the question of a constant or variable va- 
lence:? 
‘*Since the aim of all scientific investigation is to exhibit 
the most variable phenomena as dependent upon certain active 
invariable factors taking part in them and in such a manner 
that each phenomenon appears to be the necessary result of 
the properties and reciprocal action of these factors, then itis 
clear that chemical investigation would be considerably ad- 
vanced were it possible to prove that the composition of chem- 
ical compounds is essentially determined by the valency of the 
atoms and the external conditions under which these atoms 
react upon one another. ‘The first necessary step in this di- 
rection has been made in the attempt to explain the regulari- 
ties observed in the composition of chemical compounds, by the 
assumption of a constant power of saturation or an invaria- 
ble valency of the atom. The opposite and equally hypothet- 
ical assumption that the valency is variable leads to no ad- 
vancement. 
‘The first step towards progress in this matter would be 
1 Modern Theories of Chemistry, Eng, Trans., p, 303. 
