SOILS AND FERTILIZERS. 117 



postpone it to Winter ; but that is to run the risk of 

 embarrassment by frost or snow, and encounter the 

 certainty that your material will be inferior in 

 quality, or not so well fitted to apply to grain-crops 

 the ensuing Fall. 



All this, you may say, is not instruction. We 

 ought to know exactly what lands are enriched by 

 Gypsum, and what, if any, are not ; why these are 

 fertilized, why those are not, by a common appli- 

 cation ; how great is the profit of such application in 

 any case ; and what substitute can most nearly sub- 

 serve the same ends where Gypsum is not to be 

 had. I admit all you claim, and do not doubt that 

 there shall yet be a Scientific Agriculture that will 

 fully answer your requirements. As yet, however, 

 it exists but in suggestions and fragments; and 

 attempts to complete it by naked assertions and 

 sweeping generalizations tend rather to mislead and 

 disgust the young farmer than really to enlighten and 

 guide him. At all events, I shall aim to set forth 

 as true no more than I know, or with good reason 

 confidently believe. 



I close by reiterating my belief that no farmer ever 

 yet impoverished himself by making too much ma- 

 nure or by applying too much of his own manufac- 

 ture. I cannot speak so confidently of Twying com- 

 mercial fertilizers; but these I will discuss in my 

 next chapter. 



