400 LABILITY AND ENERGY IN RELATION TO PROTOPLASM. 
writes : “ Chemical energy is to us the least known of all the 
various forms of energy, as we can measure neither it nor any of 
its factors directly. The only means of obtaining information 
regarding it, is to transform it into another species of energy. It 
passes most easily and completely into heat.’’ 7 Later on (1) he 
declares : “ Chemical energy can be separated into two factors, 
intensity and capacity. The doctrine of the intensity of chemical 
energy embraces a large part of those phenomena that were 
called affinity.” 
I have adopted the definitions of Grant Allen ( 1 . c.) : “Che¬ 
mical affinity is the force that aggregates atoms, chemical energy 
is motion which separates atoms and resists the aggregation of 
atoms.” “ Force and Energy, the aggregative and the separative 
powers are incessantly opposing and antagonising one another in 
all bodies, great or small. The amount of aggregation reached 
by any system at any point of time depends upon the relative 
proportions of its forces and its energies at that moment.” 
This holds good also for the complicated molecules of organic 
chemistry. In a very stable compound, the force of affinity be¬ 
tween its atoms preponderates, and only a small amount of energy 
is present. (2) On the other hand, substances that very easily 
enter into reactions can hold their components only loosely bound , 
and the force of affinity is here counteracted by chemical energy. 
Atoms are in an unstable equilibrium when a minute amount of 
work suffices to lead to an alteration in the system ; such atoms 
have chemical energy. 
But we must carefully distinguish between several kinds of 
instability. There evidently exist substances, certain atoms of 
which merely possess potential chemical energy relatively to the 
other atoms in the same molecule, as in the case of oximes and 
nitro-compounds where the oxygen linked to nitrogen possesses 
energy of position ” with respect to the carbon atoms. In cer¬ 
tain other cases, however, atoms may possess, with respect to 
others in the same body, kinetic chemical energy , being in a 
continuous vibrating motion. But doubtless, there are also 
(1) Chem, Central-Bl. 1894. 1. p. 4. 
(2) The compounds are, of course, here considered merely with regard to their 
chemical structure, i.e. to the relative position of their own atoms ; not in their relation 
to other bodies. Everybody knows, e. g., that in relation to free oxygen all organic sub¬ 
stances contain potential energy. 
