13 



first, the second, and the third 9 inches of depth. In 

 the mixture of the 8 samples from each plot, and to 

 each depth, the nitrogen has been determined, and in 

 some the carbon also. In a few also the nitrogen as 

 nitric acid was determined. 



In July 1868, during drought, and in January 1869, 

 when the land was saturated, samples were taken from 

 3 plots, in each case to 12 depths of 3 inches each, or 

 to a depth of 36 inches in all ; and although the chief 

 object was to determine the difference in the amount of 

 water retained on the differently manured plots, at t In- 

 different depths, the nitrogen, and in some cases the 

 carbon, were also determined. 



Lastly, in 1881, samples were taken from 20 plots, 

 in each case from 6 places on the plot, and in each to 

 3 depths of 9 inches, or to a total depth of 27 inches. 

 In the mixed samples representing, respectively, the soil 

 at each depth, from each differently manured plot, the 

 total nitrogen, the carbon, the nitrogen as nitric acid, 

 and in some cases the chlorine, have been determined. 

 Partial determinations have also been made in a few of 

 the individual or unmixed samples. 



The nitrogen results relating to the surface soils, 9 

 inches deep, of the 11 plots sampled in 1865, were 

 published in No. 57, p. 137 (1881-82). The nitrogen in 

 10 of these, and in the same 10 in 1881, was given 

 in No. 60, p. 32 et seq. (1882). 



The nitrogen as nitric acid in the soils was first 

 determined in 1866, in a few of the 1865 samples, and 

 the results were given in the original paper of which 

 No. 25 is the abstract ; and referred to in No. 60, p. 48. 

 The nitrogen as nitric acid in the soils of 4 of the 

 20 plots in which it was determined in the 1881 samples, 

 and at each of the 3 depths of 9 inches each, was given 

 in No. 60, p. 49 ; and for the whole 20 plots, to the 3 

 depths, in No. 64, p. 21 and context. 



Determinations of nitrogen by soda lime have been 

 made in all the above-enumerated mixed samples of the 

 wheat field subsoils, and the results are of much 



