No. 85. J 63 



science, and Liebig and Johnston, by the extent and success of their 

 interrogations of Nature, have given to agricultural chemistry almost 

 the aspect of a new science. 



It was early found that the perfect analysis of soils, required a more 

 thorough acquaintance with chemical processes, and a more exten- 

 sive and costly laboratory, than could be generall}' expected, and that 

 a multitude of the original elements of soils were present in such 

 small quantities, or under such circumstances, as to show they could 

 be scarcely essential to the success of the crops usually grown by the 

 farmer ; and their total absence in some cases, or their presence in 

 the smallest appreciable quantities, proved that such was the case. 

 The more important original elements, however, those which the ana- 

 lysis of the plants themselves, as well as of the soil producing them, 

 proved to be essential to their perfection, was found in such quanti- 

 ties, and so easily determined, as to render a general knowledge of 

 the soil, — that knowledge so essential to the practical fafmer, — of com- 

 paratively easy acquisition. The processes for ordinary analysis have 

 accordingly within a few years been much simplified and improved, 

 so as to be within the power of almost any one who chooses to un- 

 dertake the task of investigating the character of the soils he culti- 

 vates ; while the more delicate processes necessary for a refined and 

 perfect analysis are left for the laboratory of the professed chemist. 



Cultivated soils are composed of certain earths, salts, and vegeta- 

 ble matter, and as a general rule it may be stated that in the tempe- 

 rate zones, and under ordinary circumstances, the earthy part of soils 

 does not vary far from 90 to 96 per cent. The salts are of course in 

 small yet active quantities ; and the vegetable matter ranges from half 

 per cent., to 70 or 75. The essential earths, — those on which the pe- 

 culiar qualities of all soils are based, — are sand, clay, and lime, or the * 

 compounds formed of silex, alumina^ and calcium. There are other 

 elements entering into combination with these, but it is on these, and 

 the relative proportions they bear to each other in the soil, that their 

 fertility is depending. Pure sand, clay, lime, or vegetable matter, will 

 not produce healthy plants, or indeed in most cases, any vegeta- 

 tion, however imperfect ; it is the mixture or combination of these 

 that constitute a fertile soil, and analysis is the method by which the 

 nature of these combinations, and the proportion of each element, is 

 made known. 



