458 SELECTIONS FROM ADDRESSES. 



which flourish best near the sea shore. It is not known what 

 part the chlorides play in the vegetable economy, but their con- 

 stant presence seems to indicate that they are in some way 

 useful. 



Oxides of iron and manganese doubtless perform useful func- 

 tions in the vegetable economy, for they are always found in 

 the ashes of plants. The oxide of iron, derived from vegetable 

 food, enters into the composition of blood, and is supposed to 

 be one of the vehicles for the transportation of oxygen to dif- 

 ferent parts of the body, in the circulating blood. These ox- 

 ides being universally present in the soil, there is no need of 

 supplying them by artificial means. More frequently we have 

 to neutralize the action of their salts, for some of the soluble 

 salts of oxide of iron are highly injurious, and destroy tender 

 herbaceous plants. Lime and ashes are the most common 

 amendments used in case sulphate of iron exists in the soil, and 

 by their action new and valuable saline manures are produced. 



The few mineral substances I have named, are the chief in- 

 organic constituents of plants of all kinds. Hence they are 

 universal fertilizers, and we have to examine the soils to ascer- 

 tain their presence, and the proportions in which they exist, 

 and to determine the condition that is most favorable to vege- 

 tation. We have also to ascertain the cheapest and best meth- 

 ods of supplying those ingredients that are wanting, or are de- 

 ficient in quantity, or to alter the condition or combinations of 

 those that are not in their most favorable state. 



The relative proportions of the different mineral salts, re- 

 quired for each different crop, is a study of much interest, and 

 this inquiry is now occupying the attention of distinguished 

 chemists, who will, in the course of time, discover much that 

 will prove useful in directing the labors of the husbandman. 



In the present advanced state of chemical science, new analy- 

 ses of plants and of the soil can be advantageously made, and 

 the highest skill of analytic chemistry is required in this most 

 important department of agricultural science. Rude and im- 

 perfect analyses are of no use, and only tend to lead the farmer 

 astray. Hence all the " short cut methods " proposed in news- 



