CHEMICAL, MANURES. 15 



use of manures man acquires an almost limitless control of nature. 

 It is to the study of this second condition that the teaching of Vin- 

 cennes is especially devoted. 



As to the second condition, that is regulated by the vegetable itself. 

 All species are subject to certain variations, which may become 

 hereditary. Kaces, varieties of small importance in a botanical 

 point of view, but of great import in agriculture, have often the 

 same origin. Under the same conditions of soil and manures one 

 variety will often yield double the quantity of another. I will show 

 you a remarkable example of this. 



For three years I have had blue wheat and English wheat (with 

 red straw) under parallel culture, the soil and manures exactly alike. 

 The blue wheat did not succeed at all ; the English wheat grew 

 wonderfully. In autumn the blue wheat has a marked advantage 

 over the English wheat, but in spring, affected by late frosts, it is 

 also violently attacked by rust, while the English wheat, being more 

 backward, escapes both entirely. 



There is, then, a means resting entirely upon ourselves, and to 

 which we have perhaps not given sufficient attention. For myself, I 

 believe our vegetables are susceptible of as varied changes as are our 

 domestic animals. 



But I repeat, gentlemen, that of the three conditions which rule 

 the activity and the products of vegetation, we should occupy our- 

 selves solely with the second the choice and the quantities of 

 manures. I have recalled the other two, but to show the subject on 

 all sides, and to leave nothing in obscurity, I promised you an 

 analysis of vegetation, its agents and cause. I think I have fully 

 kept that promise. Are you tempted to reproach me with the too 

 scientific character of my study ? Our path was traced out by the 

 light of these ideas. Henceforth there can be no question of empiric 

 results. Besides, if practice is our object, science should be our 

 guide, its methods our auxiliaries, and its principles the foundation 

 of our deductions. 



Until the last twenty years it has been asserted that the farmyard 

 was our agent " par excellence " of fertility. We maintain that to 

 be erroneous, and that it is possible to produce better and cheaper 

 artificial manures than can the farmyard. 



It has been said : The meadow is the foundation of all good agri- 

 culture, because with the meadow we have cattle, and with the cattle, 

 manure. These axioms are now veritable heresies. I hope to show 

 you that agriculture to be remunerative must be founded on artificial 

 manures. With farmyard manures it is now but a question of con- 

 venience and cost. 



i To determine these important views with certainty we must remain 

 faithful to the plan traced out. 



In the first place, we must define the degrees of utility of the 

 different elements of which vegetation is composed, seek the forms 

 under which their assimilation is easiest and the useful effects the 

 most certain, and last, form from them rules by which we may 

 associate them to make the most powerftil manures^ 



