CHAPTER IV. 



THE TREATMENT OF ALKALI. 



To the average Western farmer alkali is the greatest 

 bugbear with which he has to contend in his tillage oper- 

 ations. The soils of the older Eastern States are not 

 troubled in this way and are too often deficient in alka- 

 line salts, for no soil is productive when these ingredi- 

 ents are entirely lacking. Chemically considered, alkali 

 is one of a class of caustic bases soda, potash, am- 

 monia and lithia whose distinguishing peculiarities are 

 solubility in alcohol and water, the power of uniting with 

 oils and fats to form soap, neutralizing, reddening several 

 yellows, and changing reddened litmus to blue. Fixed 

 alkalies are potash and soda. Vegetable alkalies are known 

 as alkaloids, and volatile alkalies are composed largely of 

 ammonia, so called in distinction to fixed alkalies. The 

 principal compounds or salts of the alkalies with which 

 soil is impregnated, are Glauber's salts or sulphate of 

 soda, washing soda or carbonate of soda, and common 

 salt. In much smaller proportions are found sulphate 

 of potash, phosphate of soda, nitrate of soda, saltpeter 

 and even carbonate of ammonia. A majority of the last 

 five are recognized fertilizers. The most injurious of 

 th e three principal salts is the carbonate of soda. Its prop- 

 erty of combining with vegetable mold, otherwise known 

 as humus, and forming with it, when dry, a black com- 

 pound, has given the name of black alkali lands to those 

 of which it is the principal saline constituent. In time 

 of drouth these can readily be distinguished by the dark 

 rings left on the margin of the dried-up puddles. As 



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