408 BOARD OF AGRICULTURE. 



wherein do we differ in respect to the character of corn as 

 a gatherer of natural nitrogen ? I have read with great 

 care all that Dr. Lawes has written in criticism of my 

 paper ; but I leave it with the satisfaction of believing that 

 Dr. Lawes really agrees with my views, or, I would rather 

 say, that my views appear to be based on a true understand- 

 ing of Dr. Lawes's teachings, to which I confess I am indebted 

 for the most of my opinions and beliefs on this subject. I 

 disclaim any desire to stand in the relation of a disputant 

 with Dr. Lawes. I rather claim the relation of a disciple, 

 and recognize him as my apostle and authority in this 

 investigation, and shall rejoice if it may induce him to study 

 still more closely the subject of American corn-culture, in 

 connection with our peculiar climate, and our enforced neces- 

 sity for mineral fertilizing, with continuous cropping to a 

 great extent. 



In conclusion, I would say that I am much pleased to have 

 so favorable an opinion in regard to the permanence of min- 

 eral fertilizers from Dr. Lawes, when he says that "phos- 

 phoric acid and potash enter into fixed compounds with the 

 soil, and are only recovered over long periods of time." 

 American farmers can scarcely have any more encouraging 

 evidence of the permanence of artificial fertilizers than the 

 fact, that at Rothamsted the potash and phosphoric acid 

 applied thirty years ago are still showing their effects upon 

 the crops. In my attempts to grow corn continuously (and 

 chiefly with artificial manures), I have already had evidence 

 of the same fact ; and if the most costly ingredient f)i these 

 fertilizers, viz., nitrogen, is required only in the small pro- 

 portion admitted by Dr. Lawes, I can see my way clearly to 

 grow corn cheaper than I can buy it from Western farmers, 

 and either feed it in my dairy, or dispose of it at a profit. 



THE NITROGEIS' SUPPLY 



J. B. LAWES, LL.D., F.R.S. 



At Rothamsted, in the middle of May of the present jear, 

 I planted a few seeds of corn, whicli I had received from a 

 gentleman living in Baltimore, upon that portion of my land 

 which has grown a permanent wheat-crop for forty years 

 without the application of any manure. 



