13G Composition of Waters of Land-Drainage and of Rain. 



not t1ia.t wc know that these waters are extreme instances, and 

 that in all probability such a loss rarely if ever occurs in ordi- 

 nary farmin<i^. Instances will very shortly be adduced in con- 

 firmation of this fact ; and in the meanwhile it is to 1)e borne in 

 mind, that Mr. Paine is in the habit of using on his land large 

 quantities of such substances as hair, horn-shavings, woollen rags, 

 &c., to which in all probability this large quantity of nitric acid 

 is to be referred. 



As far as our present knowledge goes, we must view the 

 nitrogen of nitric acid (nitrates) in the same light as to agricul- 

 tural value as that of ammonia. All recent experiments — 

 amongst others, those of the late Mr, Pusey — seem to point to 

 this conclusion. Indeed the French chemists are going further, 

 several of them now advocating the view, that it is in the form 

 of nitric acid that plants make use of compounds of nitrogen. 

 With this view I myself do not at present coincide ; and it is 

 sufficient here to admit, tliat nitric acid in the form of nitrates 

 has at least a very high value as a manure. What then must we 

 think of drains running gorged with water, every gallon of which 

 contains as much as 12 or 14 grains of nitric acid ? 



Fifty-four parts of nitric acid contain the same quantity of 

 nitrogen as 17 parts of ammonia, or, in round numbers, 3 parts 

 of this acid represent 1 part of ammonia. Consequently, in the 

 samples Nos. 2, 3, and 7, we have a value equal to 4 grains of 

 ammonia or about 24 grains of guano in each gallon of water. 



Before proceeding further in this calculation, it will perhaps 

 be well to take other instances, which will serve materially to 

 modify the feeling of alarm which such a state of things is likely 

 to create. The samples sent to me by Mr. Acland were a series 

 of twelve, judiciously selected ; of these I have only as yet been 

 able to examine six or seven, and those only for nitric acid and 

 ammonia ; indeed, as Mr. Paine's samples represent land of the 

 highest degree of fertility, and excessively manured, Ave may 

 almost ccmsider it as a settled point that no practical loss of 

 phosphoric acid or potash, the most important mineral substances, 

 occurs in drainage, and that further analyses for such substances 

 are unnecessary, unless it be to ascertain whether any deviation 

 from this rule occurs either in the case of shallow drains or poor 

 sandy soil. 



The samples from Mr. Acland as yet examined are thus de- 

 scribed : — 



" No. 1. — Poor clay tillage field. (Hatcliclose on" Newland.) — Drained 

 about six years since. Summer before this yoimg grass dressed with dung ; 

 fallowed for turnips ; present crop now in groimd manured with dung and 

 1-2 cwt. of super[ihosphate, also with guano and wood aslies ; drained with '1 

 inch pipes, about 3 feet deep ; water continually running for last three weeks." 



