PRELIMINARY OBSERVATIONS. 6 



where lands have been cropped for a long time, these matters become so far diminished 

 in quantity that a profitable cultivation ceases. The object, then, of the analysis of plants 

 is to ascertain what elements enter into their composition, and how much is requisite to 

 give that perfection which is most profitable to the cultivator. And it is upon this kind of 

 knowledge that the most profitable rotation of crops is based ; for, as has been stated 

 already, plants differ among themselves as it regards the special elements which they re- 

 quire, and also in the relative amount of those elements ; and hence it is possible to devise 

 an expenditure of a store of food in the soil, which shall ultimately end in a great saving 

 of labor, as well as an increase of direct profits. 



To carry out the objects here alluded to, numerous analyses of plants have been under- 

 taken, the results of which it is proposed to give in this volume. I should perhaps proceed 

 at once to this part of the work ; but it seems best, in the first place, to state somewhat in 

 detail the characters of those elements which constitute so much that is essential to the 

 plant. I shall first recount all that seems to be essentially necessary for the farmer to 

 know concerning the functions or offices of the elements of plants ; and I do not, therefore, 

 here take it for granted that my readers are already familiar with these subjects ; for expe- 

 rience in these matters not unfrequently proves that our readers or hearers know less than 

 we expected, and, in fact, are ignorant of many things of which we by no means had 

 supposed it possible. I would wish certainly to pursue a plan in which plainness and 

 simplicity shall appear prominent, and which shall be as free as possible from subjects that 

 have not been explained to ordinary readers. 



We may then regard it as an essential part of the attainments of a farmer, to possess 

 a knowledge of those bodies which enter into the composition of the plants which he 

 cultivates, and even of all plants, inasmuch as they minister directly or indirectly to his 

 interests. Regarded in a general point of view, it is not difficult to see in what way they 

 affect his interests ; even in vegetables, though they do not contribute to his nourishment, or 

 that of his cattle, still their office must be taken into account. It is better that a field be 

 covered with vegetation, than to lie naked. In the former case, the growing plants bring 

 up from beneath, and to the surface, elementary substances which, if properly managed, 

 can not fail of contributing to the growth of a succeeding crop. That which it is necessary 

 to know upon this subject, is what particular nutritive elements are brought to the surface, 

 which, by decay, will remain for the improvement of the crop we propose to cultivate. 

 What elements, for example, t does the growing buckwheat bring up to the surface, which, 

 when ploughed in, shall become food for wheat or maize 1 This question can be answered 

 only by an analysis of the ash of the plant itself. This being correctly performed, we 

 shall then know not only what elements are mixed with the surface soil, but we possess 

 facts by which we can determine the amount we have in the crop of buckwheat also. So 

 too we may know how rapidly we exhaust the store of food by the continual raising of a 

 given crop. By such researches, we connect the character of the elements with that of 

 the vegetable of which they form a constituent portion, and we connect the elements of 

 the vegetable with vegetable and animal life. 



