Solvent Action of Drainage-Water on Soils. 31 



running after the dry weather of the autumn, and collected 

 some of the drainage-water, which I subjected to a partial 

 analysis, the particulars of which were described in a paper 

 read by Dr. W. Gregory at a meeting of the Royal Society, 

 Edinburgh, in the early part of last year. The results I then 

 obtained, though very incomplete, were quite sufficient to 

 show me that they had a very important bearing on agricul- 

 ture, and to induce me to go on with their further investiga- 

 tion. 



About the usual quantity of rain had fallen during the time 

 between November, vhen I collected the first sample, and 

 April 29th, when I obtained the second, and during the whole 

 of that period the land had laid ploughed as a winter fallow. 

 Immediately after the second sample was taken the field 

 was prepared for seed and sown with guano and barley. In 

 a few days after (May 16th) I was enabled to collect a third 

 sample (of course from the same drains), and having sub- 

 mitted them to analysis, the following are the results : — 



Second Sample. — 18 lbs. of drainage-water on evaporation 

 gave 15-2 grs. of solid residue, or about -844 gr. to the pound. 

 Organic matter and water in combination 3'4 



Silica 0*9 



Silicate of alumina 0*4 



Chloride of magnesium 1-12 



Chloride of sodium 1-8 



Chloride of calcium 3-0 



Sulphate of alumina 0"85 



Peroxide of iron 2*1 



Phosphate of lime 0'3 



13-87 

 TIdrd Sample. — 18 lbs. of drainage- water on evaporation 

 gave 27-5 grs. of solid residue, or about 1-525 gr. to the pound. 

 Organic matter, &c. ... 7-8 



Silica 0-7 



Silicate of alumina . . . . 0-2 

 Peroxide of iron .... 2-25 

 Phosphate of magnesia , . 1-8 



Magnesia ? l'G9 



Chloi-ide of sodium . . . 2-G15 

 Chloride of calcium . . . 2*107 

 Carbonate of lime .... 2*7 

 Phosphate of lime .... 3*1 

 Phosphate of alumina . . . 0-45 



25-412 

 I should here observe that the first sample, collected in 



