50 



acid, sometimes that as ammonia, and the chlorine, have 

 been determined at Eothamsted, either in each indivi- 

 dual sample collected from each plot, or in mixed 

 samples representing several successive collections, 

 when these have been from continuous, or nearly con- 

 tinuous, rainfalls. 



The results relating to the amounts, and to the com- 

 position, of Rain and Drainage-waters, are of great 

 interest and importance. Those relating to the amounts 

 of rain, in their bearing on the growth of different 

 crops, have been summarised and discussed in Nos. 1, 

 2, 31, 39, and 48 (Series 1). The first results relating to 

 the composition of rain-water were published in 1854 

 in No. 6 (Series 1). Some relating to the composition of 

 the drainage-waters collected in the experimental wheat 

 field are given and considered in No. 33 (1873) ; and in 

 No. 39 (1876), a summary relating to rainfall, drainage, 

 and composition of drainage, is given. In 1881-82, in 

 No. 57, most of the results obtained up to that date, 

 relating to the amount and composition of rain-water, 

 to the amount and composition of the drainage waters 

 passing through the 20, 40, and 60-inch " drain-gauges." 

 and to the composition of the drainage-waters from the 

 experimental wheat-field plots, are recorded, and dis- 

 cussed in considerable detail ; and, in the separate 

 copies of the paper, Appendix Tables are added, which 

 record in detail, the about 1,500 determinations of 

 nitrogen as nitric acid, and of chlorine, respectively, 

 made in the drainage-waters from the differently 

 manured plots in the experimental wheat-field, collected 

 from December 1866 to May 1882 inclusive. Since 

 that date, about 2,000 determinations of nitrogen as 

 nitric acid, and about the same number of chlorine, also 

 occasionally some of ammonia, have been made, in the 

 drainage- waters from the different plots. In No. 63 

 (1883), new determinations of ammonia, chlorine, and 

 sulphuric acid, in rain-water are given. Lastly, the 

 results as to the amounts of rain, and of drainage 

 through the 20, 40, and 60-inch deep drain-gauges, are 

 given for 20 harvest-years, to August, 1890, inclusive, 



