CHAPTER IX 



ELEMENTARY CONCEPTIONS OF CHEMISTRY IN 

 RELATION TO THE SOIL 



Difficulties of chemistry The elements and their symbols 

 Atoms Mixtures and compounds Molecules The formula 

 and the equation Affinities Grouping in the molecule 

 The structural formula Acids, neutrals, and bases The 

 COOH group Series of acids Seventeen possible acids 

 with one formula Neutralization of acids Oxidation 

 Reduction Hydration Dehydration Ammonia Carbo- 

 hydrates, proteins, fats, and amides. 



FEW subjects present such impenetrable difficulties 

 to those who have not made some sort of a set study 

 of it as Chemistry. Range through the Arts and 

 Sciences as you will, and the subject-matter of them 

 obtrudes itself on your everyday life. Zoology 

 seems simple and intelligible to those who have not 

 studied it, because such people think of it in terms of 

 the animals with which they are familiar. Our 

 everyday knowledge of plants makes all of us some- 

 what of amateur botanists. The man who can 

 recognize the Great Bear and a half-dozen of the 

 constellations feels confident that if he set his mind 

 to it he could become an astronomer. The bicyclist 

 imagines himself to be, and to some extent is, an 

 engineer. Experience of roads and soils makes most 

 men in a way geologists. Electric light and motor- 



