440 BOARD OF AGRICULTURE. 



To secure that amount in a more definite form than as a 

 general rule has been customary, improves most decidedly 

 our chances to ascertain, not only the special wants of the 

 plants under cultivation, but to recognize also the particular 

 form in which the various elements of plant food exert their 

 most valuable influence on the quality of the crops. Believ- 

 ing in the correctness of these views, I entered a few years 

 ago upon a series of analytical chemical inquiries to deter- 

 mine the character of the ash constituents of fruits, and to 

 study, also, the relations which apparently exist between the 

 variations in the composition of the former and the quality 

 of the latter, for the purpose of furnishing information needed 

 for the successful introduction of a rational system of ferti- 

 lization of oviV fruit-hearing plants. ^^ 



These investififations have been carried on since without 

 serious interruption, as far as the limited resources of past 

 years for experimental work of that character have per- 

 mitted. The scarcity of previous systematic chemical in- 

 quiries into the relations existing between the kind and the 

 amount of available plant food in a productive garden soil 

 or orchard, and the absolute and relative quantity of the 

 various soil constituents contained in the fruit and garden 

 crops raised upon it, rendered it necessary to grow them 

 under well defined circumstances, to obtain material fit for 

 comparative analyses. 



The necessity of adopting that course of action became 

 still more apparent, when considering the extraordinary in- 

 fluence — quite generally conceded — of soil, location and 

 season on the quality of these crops. Products raised by 

 the aid of difterent manurial substances, within the same 

 season, upon a similar soil, and of a corresponding stage of 

 growth, had to be secured for the examination, to impart a 

 scientific and practical value to the analytical results. 



It is a well-known fact that the absolute amount of the 

 mineral constituents of plants of the same variety, and of 

 one and the same species, even, may differ widely, yet, as a 

 rule, this circumstance does not necessarily alter the general 

 character of the plants. 



A change, however, in the relative proportion of the vari- 

 ous mineral constituents, as potassa, lime, etc., rarely has 



