RECENT SCIENCE. 811 



RECENT SCIENCE. 



By P. KEOPOTKIN. 

 I. 



THE world of chemical phenomena is so immensely wide, and 

 the phenomena themselves are so complicated, that the 

 founders of modern chemistry were compelled to limit the area 

 of their investigations, and sharply to separate their own domain 

 from those of the two sister-sciences, physics and mechanics, 

 leaving it to the future to find out the bonds which might unite 

 all three branches into one harmonious whole. They and their 

 followers elaborated their own methods of investigation; they 

 discovered their own chemical laws and worked out their own 

 hypotheses and theories; and, with the aid of these methods, 

 laws, and hypotheses, they created a science which not only in- 

 terprets, discovers, and predicts the phenomena it deals with, but 

 already has brought us within a measurable distance of a general 

 theory of the structure of matter altogether. 



In proportion as chemical research went deeper into the study 

 of the wonderful movements and interactions of molecules and 

 atoms, the intimate connection which exists between chemistry, 

 physics, and mechanics became more and more apparent. The 

 physical and the chemical properties of matter proved to be so 

 closely interdependent that they could be explained no longer 

 with the aid of chemical theories alone; the very fundamental 

 laws of chemistry appeared to be but so many expressions of 

 physical facts ; and chemistry stands now in such a position that 

 no further advance in its theoretical part is possible, unless it 

 enters the border-land which separates it from physics, recognizes 

 the unity of chemical and physical forces, and, availing itself of 

 the progress recently made in molecular mechanics, boldly attacks 

 the great problem of a physical that is, a mechanical interpre- 

 tation of chemical facts. This is the work which now engrosses 

 the attention of most chemists. 



The points of contact between physics and chemistry are very 

 numerous, and the work is being carried on in several directions 

 at once. The discovery by Mendeldeff of the so-called " periodical 

 law of elements " has called into life numerous researches, some 

 of which accumulate correct numerical data to express the de- 

 pendence between the physical properties of various bodies and 

 their chemical constitution; while others endeavor to interpret 

 this very periodicity in the properties of the elements under the 

 assumption of their compound nature. On the other side, the 

 recent development of the mechanical theory of heat, and the 



