Composition of Waters of Land-Drainage and of Rain. 133 



these are the exception, not the rule ; and it Mas my object to 

 detect the subtle and insensible loss which might occur to land 

 Avhere no indications except those furnished by chemical analysis 

 could have marked its existence. 



The ibllowing Table exhibits the analysis of the seven first 

 samples described by Mr. Paine, so far as relates to the mineral 

 constituents properly so called. These are all the mineral 

 analyses of drainage-waters that I have yet made. The quantity 

 of ammonia, nitric acid, and organic matter, will be stated im- 

 mediatelj- : — 



Table III. — Water of Lund Drainage — Mineral Contents. 

 (Grains in an imperial gallon.) 



Upon examining this Table we find that the substances which 

 ■are found in drainage-water in largest proportion are lime, mag- 

 nesia, soda, and sulphuric acid. That the quantity of lime 

 should be ctmsiderable in some instances, especially where, as 

 in the district in question, the land contains so much of it, 

 should hardly surprise us. Carbonic acid, which exists in 

 rain water, and is furnished in large quantity by cultivated soils, 

 readily dissolves carbonate of lime, and the great bulk of the 

 water of the chalk district comes in this way to contain from 15 

 to 2() grains of this carbonate in the gallon. The sulphuric acid, 

 which to a great extent occurs in the waters in the form of sul- 

 phate of lime, may either exist in the soil in that form, or may 

 have resulted from the use of superphosphate, which alwavs 

 contains large quantities of sulphate of lime. It might also be 

 librTatcd from the various substances of an animal nature, such 

 as horns, hoofs, rags, &c., which Mr. Paine uses, and which con- 

 tain sulphur. 



The quantities of soda and magnesia are in some cases rather 

 large. " They must, I imagine, have been derived from the soil, 

 for apparently no portion of either has been applied in manure. 

 It will presently appear that, in all probabilitv, the presence of 

 these substances in quantity is connected with that of nitric 

 acid. 



