Pattern—Solutions of Hydrochloric Acid in Solvents. 339 
each other that whatever characteristic individual attraction 
(chemical affinity) they may possess for each other may be minr 
imized. Then every substance' in solution is to act like every 
other substance since there will be so little of its own peculiar 
attraction, for its neighbors exerted when it is so far from them. 
Any attraction which the particle of matter may have for the 
particles of solvent about it is neglected. 
It is true the mathematician or physicist argues that the 
simple laws of motion and of attraction grow complicated when 
the bodies acting are numerous and close together. But in the 
case of solution, this diluting of chemical affinity does not de¬ 
stroy it and when we begin to concentrate we get back chemical 
affinity as certainly as if it had not been cast away. The prob¬ 
lem may be complicated, but it must be faced. Furthermore, 
these laws which were developed to hold for infinitely dilute 
solution, by neglecting chemical affinity, do not serve even rea¬ 
sonably w r ell for concentrated solutions, in spite of numerous 
additional assumptions. However much the physicist or math¬ 
ematician may desire to get all matter to act alike, the fact of 
chemical individuality remains to be dealt with. 
The facts show that presence of water is not a necessity in 
order that chemicals may react upon each other. A chemical 
system need not conduct electricity electrolytically in order that 
chemical action take place. Chemical individuality and chem¬ 
ical affinity are the main factors in chemical reactions, while 
temperature, pressure, surface conditions, and the masses of the 
acting substances also exert great influence upon the nature, 
direction and extent of the reaction. In general a chemical 
action goes, on in such a way that the potential energy of the 
system is reduced to a minimum. The impulses which initiate 
chemical action require further study; the probability is that 
a vibration of proper period must be set up in the system before 
chemical reaction will take place. On this basis we can under¬ 
stand why certain reactions require a definite temperature; 
likewise, why substances are stable between definite limits of 
temperature. 
Some have taken the position that two pure substances can¬ 
not unite—an easy thesis to defend if one assumes that man 
