128 Thoughts on Chemical Affinity. [March, 
at discordant periods— in which they might persist to some 
extent, despite their mutual influence — could not form a 
stable combination, is equally unquestionable. Although in 
all such cases magnetic affinity might seek to produce com- 
bination, without regard to the special characters of the 
molecules, this general tendency to combine would be op- 
posed by the special resistance to combination offered by 
these diverse movements. Two molecules swinging to- 
gether in unison would support and sustain each other’s 
attractions. Two which constantly darted apart from each 
other could never form a close union, and would be con- 
stantly exposed to exterior energies. 
It needs special conditions of isolation from disturbing 
influences to bring elements of feeble affinity into combina- 
tion with each other. Such conditions are produced in 
organic nature, and thus complex molecules are built up 
whose constituents must display considerable diversities of 
vibratory pitch. The more intricate these compounds the 
less coherent are they. Their combinations are only safe 
while protected from external influences of a stronger cha- 
racter. When exposed, for instance, to oxygen, this element 
of vigorous affinity disturbs the incoherent union of diverse 
elements. The varied vibratory swings of the latter hinder 
them from coming into close and dense union. A certain 
space must be necessary for feebly accordant movements to 
take place in, and these intricate compounds, therefore, 
form molecules of slight density, verging from the solid, 
through the colloid, towards the liquid. Oxygen seizes, as 
circumstances favour it, on one after another of the outward 
swinging atoms or molecules of these compounds, and forms 
with them molecules of more harmonious motion and inti- 
mate elemental relations, so as in time to quite break down 
the large, but feebly accordant, compound of vibrating 
molecules. 
