12 On the Chemical Properties of Soils. 



of the ammonia has become neutralised by the organic matters 

 in the soil. 



The deeper coloured the ammonia solution after contact with 

 soil, the greater will be the error which will be made if the 

 amount of ammonia is determined in the brown-coloured liquid 

 in a direct manner by the alkalimetrical process. Whenever 

 the solution is distinctly coloured yellow or brown, it should be 

 first distilled with caustic potash, in a properly-constructed ap- 

 paratus, and the free ammonia be determined in the distillate. 



Thus the same ammonia solution which yielded to 1000 

 grains of this sandy soil, according to the direct process of neutral- 

 isation, 1*076 grains of ammonia in one experiment, and 1*136 

 grains of ammonia in a second experiment, after distillation with 

 caustic potash was found to contain in 1000 grains of liquid 

 119 grains of ammonia ; consequently, subtracting as before 

 119 from '332 grains, '213 grains are removed from every 1000 

 grains of liquid, or 2*982 grains from the whole solution. 



Ammonia. 

 Grains. 



In a second distillation : 



1000 grains of liquid were found to contain 'Ill 



Before contact with soil the solution contained . . . . *332 



221 



Therefore *221 grains of ammonia were removed from every 

 1000 grains of liquid, or 3*094 grains from the whole quantity. 



Ammonia. 

 Grains. 



According to the first distillation : 



1000 grains of soil absorbed -852 



According to the second distillation : 



1000 grains of soil absorbed -884 



The mean of the two direct determinations is .. .. 1-101 



The mean of the two determinations by distillation is -868 



Difference -233 



An error, amounting to one quarter of the whole of the am- 

 monia absorbed by the soil, would therefore have been com- 

 mitted had the determination not been made after distilling the 

 liquid with caustic potash. 



Fifth Experiment, on Pasture Land. 



The mechanical analysis of this soil yielded the following re- 

 sults : 



Mojsture 2*42 



Organic matter ll'TO 



Lime 1-54 



Clay 48-39 



Sand 35-95 



100-00 



