198 OF FORCK. 



One of the most important re«ults of force is the production of definite compounds : the 

 quality of force is not expended in the production of definite forms. These two results are of 

 the utmost importance. By the production of form we are furnished with one of the charac- 

 teristics of matter, the identity of species : it is true in both of the kingdoms of nature ; a kernel 

 of wheat has its characteristic form as well as a crystal of quartz, and so they have also their 

 characteristic composition ; the first is a symbol of the last — ^when we see the first we insensibly 

 recur to the last. These facts are so important that the existence of life on the globe depends 

 upon them ; if the first was not a symbol of the last the selection of food would be impossible. 

 Men seem to have acted instinctively in this matter. The laws of combination and the laws of 

 form are but recent determinations. The combinations of organic bodies may admit of greater 

 latitude than those of inorganic bodies. There is, however, always in force the law of definite 

 combination among the atoms of bodies. The modification of properties follows from the 

 slight latitude which is allowed ; the smybol or outer sign remains in force still, the slight 

 change in composition is indicated by change of property. This fact, if closely studied in con- 

 nection with analysis, would become highly useful. The cultivated sense would soon be 

 able to distinguish the glutinous wheat from the starchy ; even now, observation supplies us with 

 many characteristics by which change of composition is clearly indicated. On this subject we 

 scarcely know which to admire most, the production of definite forms, or symbol, or the pro- 

 duction of definite compositions. Our admiration will not be diminished if the former should 

 be proved to be a consequent of the other. 



There is still another important point to be noticed in this connection ; it is the infinity of 

 combinations possible among a few of the elements, as oxygen, hydrogen, nitrogen and carbon. 

 Elementary works on chemistry supply us with data on this subject. What we are most in- 

 terested in, as a fact, is the preservation of identity in each of the combinations. If identity 

 was lost by these multiple combinations, many of the designs of nature would be frustrated ; 

 but as the constitution of nature, by the distinctiveness of force, preserves the identity both of 

 living and dead matter, in all the infinity of its combinations, we are always enabled to make 

 all the proper distinctions among bodies. It is this fact which gives importance to mineralogy 

 or the study of outward forms, or the study of natural history in general. We wish for a gene- 

 ral expression of nature ; we can only obtain this by the observation of outward forms : this 

 prepares the way for another step, the connection of form with substance and combination ; it 

 is here that mineralogy and chemistry meet. A refined agriculture is interested in the promo- 

 tion of this study. The products of the soil may be modified by culture, and numerous varie- 

 ties of grain, having each their peculiar properties and uses in the economy of domestic life, 

 may be produced, which shall add to the comfort of the household. How to control the law 

 of combination, however, has not yet been determined : most of the results of change in com- 

 position and production of variety has been rather the result of accident than of well directed 

 experiment. An element which enters into these investigations is time ; for it can not be 

 doubted that the time or season of production is important. The development of modified 

 forms by change of circumstances requires a fuller investigation. Heat and light hasten the 



