POTASSIC MANURES 105 



into underground crystallizers. As the solution 

 cools in flowing through the gutters, it deposits 

 a certain amount of salt containing 45 to 50 

 per cent of potassium chloride. This gutter 

 salt is generally used in manure manufacture. 

 It is generally treated with potassium chloride 

 of a higher strength. 



The crystallizers in which the solution cools 

 and forms crystals of potassium chloride are 

 of riveted wrought iron like the clarification 

 basins; they vary in size and shape, sometimes 

 deep because they occupy less space and yield 

 larger crystal. When the solution is cold, which 

 takes two to four days, the mother liquor No. 

 2 is decanted from the crystals of potassium 

 chloride; it is run off by the gutters fixed under 

 the crystallizers into wrought-iron basins or 

 into masonry ones lined with cement. It is 

 used either to dissolve the crude salt or treated 

 directly as will be described further on. The 

 potassium salt which is deposited in the crys- 

 tallizers consists of a mixture of potassium 

 chloride and common salt; it is still soiled by 

 the adhering mother liquor. It crystallizes in 

 the same form as sylvine, with this difference, 

 that the crystals are not always perfectly formed; 

 their size depends chiefly on the density of the 

 solution of crude salt. When that has a density 

 of 32 to 33 Be. or still weaker density, crystals 

 often 1 in. wide, of a pearly lustre, are obtained. 

 When the solution is more dense, say about 



