314 Soda-Salts in A(jricullarc. 



minations of sulphuric acid and clilorine made in separate portions 

 of the filtered liquid. 



The total solution with this marly soil was found to con- 

 tain : — 



Organic matter •■140 



Sohible silica -180 



Oxides of iron and ahnuina and traces of phosplioric acid '080 



Carbonate ot" lime 2'764 



Sulphate of lime 8'506 



Carbonate of magnesia •27(5 



Carbonate of potash •252 



Chloride of sodium 1*2()() 



Sulphate of soda 30-874 



50-038 



llefore the experiment, the solution contained 44-030 = 19-C17 

 After contact with soil oG-874 = 13-283 



8-056 = 0-334 



1000 grains of marly soil accordingly absorbed 1*809 grain of 

 soda. 



In this experiment a portion of sulphate of soda acted upon 

 the carbonate of lime in the soil, and produced, in the first place, 

 sulphate of lime, a combination sufficiently soluble in water to 

 pass into solution, and carbonate of soda. The silicates in the 

 soil, or other combinations for which soda has affinity, act upon 

 the carbonate of soda and fix its base. This marly soil con- 

 tained an appreciable ([uantity of sulphate of lime, which 

 augments slightly the quantity produced by the sulphuric acid of 

 the decomposed sulphate of potash, as will be seen by the 

 following results : — 



Suliihui'ic Acid. 



The sulphate of soda in 4 dcci-gallons of solution contains 25-312 

 The total solution after contact with soil contained .. .. 25*770 



Excess -458 



This slight excess corresponds to 0-778 grain of sulphate of 

 lime. In conformity with other experiments, no absorption what- 

 ever of sulphuric acid took place. It will be seen also that Avith 

 this soil, containing 12 per cent, of carbonate of lime, the absorp- 

 tion of soda is greater when sulphate of soda is brought in con- 

 tact with it than when chloride of sodium is used. 



2. Experiment xcitJi Sulphate of Soda on Sterile Sandij Soil. 



In this experiment a solution of sulphate of soda was used of 

 the same strength as before. The soil was the same as that upon 

 which the filtration experiment with chloride of sodium was tried ; 



