Analysis and testing of soil ingredients

1193. The relative proportion of the ingredients of soils varies very greatly. According to the analyses given in Dr. Sprengel's book on the Composition of Soils, and quoted by Professor Solly, it appears that silica in the form of sand constitutes above nine tenths of some of the most fertile soils in Germany. The other constituent parts of one of these soils, according to Dr. Sprengel, were as follow: humus, containing nitrogen, humic acid, oxides of iron and manganese, alumina, magnesia, lime, chiefly combined with the silica, phosphoric acid, potash, soda, sulphuric acid, and a very small proportion of chlorine.