Soda-Snifs in Af/riculfure. 303 



Absorption of Soda. 



With a view of throwing-, if possible, further light on the 

 functions of soda-salts, and more especially of common salt, in 

 relation to the soil and the crops grown upon it, I have made some 

 experiments similar to those recorded in my paper on the ' Ab- 

 sorption of Potash by Soils of known Composition,' and have 

 now the pleasure of laying before the Society a further instalment 

 of soil studies, similar to those which will be found in previous 

 volumes of this Journal. 



Experiments with a solution of Chloride of Sodium. 



In the following four experiments ^ lb. (3500 grains) of soil 

 were in each case introduced into a glass-stoppered bottle, four 

 deci-gallons of water containing in solution 41*52 grains of 

 chemically pure chloride of sodium were then poured upon the 

 soil and left in contact with it for four days, during which 

 time this mixture was shaken up at intervals and then allowed 

 to settle. The clear liquid was then syphoned off and passed 

 through fine filtering-paper. In separate portions of the per- 

 fectly clear filtered solution the following substances were then 

 determined by well-known and approved analytical processes 

 that need not be described here in detail : — 



Soluble silica ; oxides of iron and alumina (together) ; lime ; 

 magnesia ; potash ; soda ; sulphuric acid ; phosphoric acid, and 

 chlorine. 



The amount of sulphuric acid found in the analysis was com- 

 bined with its equivalent proportion of lime, and calculated for the 

 whole four deci-gallons. The chlorine found was combined with 

 the magnesium, potassium, sodium, and with the remainder of 

 the lime found in each analysis. 



Experiment No. 1. — With a solution of Chloride of Sodium, on 

 a Calcareous Soil. 

 The soil employed in this experiment was a chalk-marl, con- 

 taining carbonate of lime in a greatly preponderating proportion, 

 with but little clay and organic matter, as will be seen by the 

 following analysis, which gave in 100 parts : — 



Moisture 3-62 



Organic matter 4'23 



Carbonate of lime 67"50 



Oxides of iron and alumina 7"54 



Magnesia "44 



Potash and soda ''•79 



Insoluble silicious matter 15'88 



Clilovine and pliosplioric acid traces 



100-00 

 , VOI^. I. — S. S. X 



