166 SCIENTIFIC THOUGHT. 



1826 marks the revival of mathematical studies in 



Germany through the appearance of Crelle's journal ; so 



43. the year 1887 saw the first number of Ostwald and 



Ostwald's 



journal. Vau't Hoff's ' Zeitschrift flir physicalische Chemie.' From 

 that period the physical properties of chemical substances,, 

 so long neglected, or only studied by isolated students, 

 have received systematic, mathematical, and exact 

 treatment, guaranteeing something like continuity and 

 completeness, and leading on to the solution of the great 

 remaining question. What is chemical affinity ? 



The eminent natural philosophers to whom is mainly 

 due the foundation of this modern science, claim also to 

 be gradually realising the idea which was suggested ])y 

 the early representatives of the theory of energy — 

 notably by Eankine and James Thomson — ^that of a 

 general doctrine of energy, termed energetics ; and they 

 hold that this suggestion is only realisable by breaking 

 with the conventional ideas which the older physical 

 theories — the astronomical, atomistic, and kinetic views — 

 have imposed upon our reasoning. They further hold 

 that the gradual development of chemistry into an exact 

 science necessarily requires the introduction of this 

 broader view which they embrace, and that the older 

 views — useful in their way — only suffice to comprehend 

 certain restricted groups of natural phenomena, whereas 

 in chemical changes, where all imaginable natural pro- 

 cesses seem to come together, a laro-er and more inde- 

 pendent theory is indispensable. It is interesting to 

 note how very generally they trace this larger view to 

 the long unnoticed labours of a natural philosopher in 

 the New World, Professor Willard Gibbs of Yale. 



