J. E. TESCHEMACHER'S ADDRESS. 609 



other substances. Peat muck, for instance, is usually accom- 

 panied by acids injurious to vegetation, either ready formed, or 

 by substances which, on exposure to the external influences of 

 the air, form these acids. — this renders sweetening or neutrali- 

 zation of these acids necessary previous to using it. 



The manures of various animals are also mixed with phos- 

 phates and other salts, often of ammonia, which are very 

 beneficial to vegetation, but the chief mass is vegetable fibre, 

 which by proper management becomes this powerfully absorb- 

 ent charcoal. I wish much to impress very strongly on your 

 attention this character of absorption by charcoal, as it is the 

 chief groundwork of the subject of this address. 



The other absorbent of the valuable portions of manure is 

 clay. This I shall not undertake to describe to those whsD^ 

 know so well what it is, but will state, that its powers of ab- 

 sorbing and retaining the important alkalies, potash, soda, 

 ammonia, and the salts of these alkalies, exceed those of 

 charcoal. As a large proportion of the clay of this globe ex- 

 isted originally in the shape of feldspar, a constituent of granite 

 and other rocks from which it has been separated by natural 

 grinding down and disintegration, and then becoming a portion 

 of other rocks, it of course formerly entered into the compo- 

 sition of many soils. From the more coarse, sandy and stony 

 of these, it has been washed away in the lapse of ages ; still 

 many of them have a considerable proportion left, and in the 

 trials made to ascertain the absorbing and retaining power of a 

 soil, the amount of this power observed will probably be more 

 due to the clay remaining therein than to any natural char- 

 coal, which is not often found in sandy or loamy soils, but 

 which is a large ingredient of the rich bottom lands and prai- 

 ries of the fertile west, they being chiefly formed of decom- 

 posed animal and vegetable matter. The finest and most 

 productive loams, the marls which in some places are used for 

 manure with good eff*ect, when there is not too much lime in 

 them, are valuable on account of the absorbent power of the 

 clay and of the salts of potash and soda then in its grasp. 

 In the estimation of the value of land, then, the quantity of 

 clay, if appreciable, forms a most important item. Three or 

 77 



