120 MANUFACTURE OF FERTILIZING MATERIALS 



composition, the proportion of silica to alumina 

 is less than 3 to 1, but in commercial samples of 

 leucite-bearing rocks, the ratio is usually greater 

 than 4 to 1. 



A clinker of the same ultimate composition as 

 that which results when feldspar and lime are 

 heated together may also be obtained when part 

 of the lime is replaced by sufficient calcium chloride 

 to be equivalent to the potash and soda in the 

 feldspar, the total calcium used remaining the 

 same as before; in carrying out this experiment, 

 the feldspar and lime were ignited to constant 

 weight, and the calcium chloride thoroughly dried 

 by heating in an air bath below its melting-point. 

 Ten grams of the feldspar were well mixed with 

 2.0050 grams of calcium chloride and 15.7895 

 grams of calcium oxide, and the mixture then 

 ignited in an open dish in the furnace at 1400 C. 

 By this treatment the alkalies are volatilized as 

 the chlorides. On igniting for one-half hour, the 

 weight lost by the ignited mass amounted to 

 2.5632 grams, equal to 25.63 per cent of the 

 feldspar. When expressed as the chlorides, the 

 percentage of alkalies in the feldspar used, 

 amounted to 25.82 per cent. It would appear, 

 therefore, that practically the whole of the al- 

 kalies in the feldspar were volatilized during the 

 first half hour of ignition. On continuing the-, 

 ignition for one hour longer, the additional decrease 

 in weight which took place, amounted to only 

 0.0090 gram, The residue was then analyzed for 



