THE 

 LONDON, EDINBURGH, and DUBLIN 



PHILOSOPHICAL MAGAZINE 



AND 



JOURNAL OF SCIENCE. 



♦ 



[FIFTH SERIES.] 

 AUGUST 1885. 



XIII. The Polymerization of the Metallic Oxides. By Louis 

 Henry, Professor of Chemistry in the Catholic University of 

 Louvain*. 



Introduction. 



ONE of the principal objects of Physical Science, in fact its 

 principal object, is to determine the natural relation of 

 things. It is by comparisons logically established between the 

 things themselves that these relationships are disclosed. An 

 essential condition to be observed in researches of this kind 

 is to compare only those objects which are really comparable. 

 Stated in the terms of chemical science, this general condition 

 of all work undertaken with a truly scientific object consists 

 in establishing a comparison only between the chemical mole- 

 cules themselves. Molecules are, in fact, for the chemist the 

 veritable chemical individuals — they are the bodies themselves 

 in their simplest, and at the same time their most complete, 

 expression. Molecules find a graphic representation simple 

 and concise, and sometimes even sufficiently perfect, and in 

 every case susceptible of a great degree of precision, in the 

 chemical formulae at present in use. 



Formulae, however, only maintain their full and complete 

 utility so long as they are the exact and complete representa- 

 tion of the molecules of bodies, — of bodies between which che- 

 mical actions occur, of bodies which we possess in reality, and 

 which are the veritable objects of our comparisons. This re- 

 presentation becomes exact and complete only when the for- 



* Communicated by Prof. Carnelley. 

 Phil. Mag. S. 5. Vol. 20. No. 123. August 1885. G 



