+----------------------+-----------------+------------+-------------+ | | Moorland soil | Sandy soil | Soil from | | | near Aurich, | near | near | | | East Friesland. | Wettingen. | Muhlhausen. | +----------------------+-----------------+------------+-------------+ | Silica and sand | 70.576 | 96.000 | 77.490 | | Alumina | 1.050 | 0.500 | 9.490 | | Oxide of iron | 0.252 | 2.000 | 5.800 | | Oxide of manganese } | trace | { trace | 0.105 | | Lime } | | { 0.001 | 0.866 | | Magnesia | 0.012 } | | 0.728 | | Potash } | } | | { trace | | Soda } | trace } | trace | { | | Phosphoric acid } | } | | 0.003 | | Sulphuric acid } | } | | trace | | Carbonic acid | ... | ... | 0.200 | | Chlorine | trace | trace | trace | | Humic acid | 11.910 | 0.200 | 0.732 | | Insoluble humus | 16.200 | 1.299 | 0.200 | | Water | ... | ... | 4.096 | | |-----------------+------------|-------------| | | 100.000 | 100.000 | 100.000 | +----------------------+-----------------+------------+-------------+ The results contained in these analyses are peculiarly remarkable, for they indicate the almost total absence of all those substances which the plant requires. They must, however, be considered as in a great measure exceptional cases, as it is but rarely that so large a number of constituents is absent, and it is much more frequent to find the deficiency restricted to one or two substances. They are illustrations of barrenness dependent on different circumstances. The first shows the unimportance of the organic matters of the soil, which are here unusually abundant, without in any way counteracting the infertility dependent on the absence of the other constituents. The second is that of a nearly pure sand; and the third, though it contains a greater number of the essential ingredients of the ash, is still rendered unfruitful by the deficiency of alkalies, sulphuric acid, and chlorine.