FERTILIZERS. 235 



by the intelligent and inquisitive farmer. Memory is not a sufficient guide in matters pertaining 

 to meteorology ; it is necessary that observations should be recorded, and that the result of 

 many years should be taken in order that the mean or average quantity of water which falls, 

 the direction of the winds, the number of cloudy days, etc., may be determined with accuracy. 

 A lartre proportion of this state has been settled within the memory of the oldest inhabitants ; 

 the forests have been cut down, water courses have been drained, and it is only within a com- 

 paratively brief period that the surface has been brought into a state which may be regarded 

 as permanent. These changes upon the surface may not influence the annual amount of rain 

 which falls generally, yet I believe that some sections of country may be permanently affected ; 

 the amount of rain will be less than when in forest, and it is possible that the manner of its 

 fall will be changed also. A rain falling in torrents will produce upon the face of the coun- 

 try an effect unfavorable to vegetation ; there may be less regularity in the spring and fall 

 rains. The temperature, taking the seasons together, may be modified. All facts which bear 

 upon these points require to be collected, inasmuch as little dependance can be placed upon 

 the isolated experience of individuals, especially where the opinions are formed from memory. 



I. The fertilizers which belong to the mineral kingdom. 



It is to be remembered that any thing may be regarded as a fertilizer which is found incor- 

 porated into the vegetable tissues ; but some of those substances are of less importance than 

 others, for the reason that nature has supplied them in sufficient abundance. The soil always 

 contains a quantity sufficient to meet the wants of vegetation. Of these substances it is proba- 

 ble that iron and manganese are always present in quantities sufficient to meet all the demands 

 of growing plants, and rarely, if ever, suffer from their absence. How this fact may prove in 

 chalk districts, where there is truly a calcareous soil, I am not informed ; but clays, sands and 

 loams, in all their varieties and mixtures, invariably contain iron sufficient to meet the demands 

 of plants. The condition of the iron, however, may not be that which favors, to the greatest 

 extent, the growth of vegetables. It is proper to observe, however, that there are occasionally 

 indications, in fruit and forest trees, of the want of iron : they become yellow and sickly. In 

 this condition, the oxides of iron from the smith's forge, cinders, etc., applied about the roots, 

 will restore energy to the feeble plant, or even when the leaves are sprinkled with a solution 

 of a friendly salt of iron, the reviving effects often speedily follow. These cases may be re- 

 garded as exceptions, and seem to be cases where the plant remains in situ many years, and 

 where the roots may be unable to penetrate into a new soil. Manganese is often detected in 

 the soil, and perhaps is always present ; its utility to growing plants has not been determined : 

 it is common in the ash of corn stalks and corn leaves. It would be unsafe to maintain that it 

 is useless because it exists only in small proportions, and is absent in many instances. 



1. Fertilizers in which lime is one of the constituents. 



It would not be proper to designate the large number of compounds in which lime is a base, 

 under the name of calcareous manures. Some of them, as quicklime, marl and plaster, are 



