4CO 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." 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. I. p. 4. 



(2) The compounds arc, 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, g., that in relation to free oxygen all organic sub- 

 stances contain potential energy. 



