162 TARANSACTIONS OF THE 



shell form. If this is dug and spread as a top-dressing, luxuriant crops 

 will grow, and if clay is added to stiffen it, corn and potatoes will repay 

 the expense. 



Wherever you observe the water-cress growing in streams issuing from 

 hill-sides, you may be assured that by digging you will find an abundance 

 of marl, or lime. By using these as top-dressing great results may be 

 obtained on contiguous lands. In fact, all farms have the proper manures 

 upon them, if the owners have sufEcient chemical knowledge to discover 

 them. If you would know the chemical constitution of your soil, analyze 

 that which grows best upon it. 



All soils undergo slow but certain natural changes as time wears on ; 

 that is to say, stiff clays become after a period of cultivation, black vege- 

 table anould, to a certain depth, produced by the decay of nourishing 

 grasses. 



The same changes take place in forests. Charlemagne was accustomed 

 to chase the deer and follow the roe, in the forest of Gerardnier, then 

 abounding with oaks, and it now only contains pines. On the river Ehine, 

 I observed forests of oaks yielding to the beech, and in other places the 

 beech yielding to pines. This is plainly indicated to the observing traveler, 

 ■who, the moment he beholds the dead top of the dying beech, will see the 

 livinof top and dark green foliage of some other tree, ready to take its 

 place. Yv^hen a forest of oak is cut down in our country, a pine forest 

 succeeds it. If pine precedes, oak succeeds. This practical hint given us 

 by nature, plainly shows that we. must fit the crop to the soil, or change 

 its nature to suit the crop. 



Among the mechanical methods by which we produce changes in the 

 soil, draining undoubtedly holds the very first and most important place, 

 as without it no man need attempt to farm. Efficient drainage permits 

 excess of rain falls to be carried off, and affords a ready escape for stag- 

 nant water, arrests the ascent of water from beneath, whether by the force 

 of springs or capillary action, preserves the surface from undue moisture, 

 and the sub and surface soil from noxious matters. It allows rain drops 

 to filter through the soil, dissolve the gypsum, which requires much moist- 

 ure, carry down top-dressings in solution, dissolve and carry off noxious 

 substances, and open the way for atmospheric air to descend through the 

 pores to the drains, thus refreshing the roots, and aerating their spongiole?, 

 besides drying, loosening, sweetening, and rendering friable the soil, has- 

 tening the growth of crops in the spring, making early the harvest in the 

 fall, and in fact changing the climate in the vicinity, besides actually 

 deepening the soil, and rendering it fit for that most important adjunct, 

 the subsoil plough, which destroys insects and weeds, reduces the land to 

 minute division, renders it pervious to the roots of corn, and permanent 

 admission of air, by the oxygen of which animal life is sustained, and by 

 its carbonic acid gas the plant is nurtured. When seeds are placed be- 

 yond its reach, they will remain for centuries without the signs of life, and 

 still capable of sprouting when exposed to its vital influence. This accounts 



