Soda-Salts in Agriculture. 313 



The soils used in this series of experiments absorbed the 

 following quantities of soda by 1000 grains : — 



Soda. 

 (No. of Grains.) 



1. Calcareous soil '800 



2. Stiff clay 1-057 



3. Fertile sandy loam '620 



4. Pasture land I'OOO 



5. Marly soil '996 



6. Sterile ferruginous sand '620 



Compared with the amount of potash which the same soils 

 removed from solutions of chloride of potassium, these quantities 

 are small, since, speaking generally, they are not more than one- 

 third or one-fourth as large.* In every instance, however, an 

 appreciable quantity of chloride of sodium was decomposed, and 

 gave rise to soluble chlorides of potassium, magnesium, and 

 calcium ; and in the case of the ferruginous sand, chloride of 

 ammonium was formed in addition and passed into solution. 



My experiments agree with those of other observers, and prove 

 that common salt is certainly an effectual means of eliminating 

 mineral food from the soil and placing it at the disposal of the 

 growing plant. 



Experiments with Sulphate of Soda. 



1. Oh a Marly Soil. 



The same soil which was used in the Experiment No. 5, with 

 chloride of sodium, was tested to ascertain its power of removing 

 soda from its sulphate. 3500 grains of the marly soil were put 

 into a stoppered bottle and mixed with four deci-gallons of a 

 solution containing 44'93 grains of anhydrous sulphate of soda. 

 The greater portion of the liquid, after standing upon the soil 

 for four days, was drawn off, filtered, and subsequently 

 analysed. 



Two deci-gallons of the clear solution, when evaporated to 

 dryness, gave a residue, weighing 25*650 grains, dried at 

 300° Fahr. 



The total solution accordingly gave 51'30 grains of solid 

 matter. 



The residue left, on evaporation, was analysed, and deter- 



* 1000 grains of soil removed from solutions of chloride of potassium, the 

 following quantities of potash : — 



Potash in grains. 



1. Calcareous soil 3*578 



2. Clay soil 3' 970 



3. Fertile sandy loam 2'626 



4. Pastvxre land 3-758 



5. Marly soil 3'373 



C. Sterile sand 1*465 



