Now, if we look at these figures we shall see how much of the mineral matter required for the clover has been previously abstracted by the barley, and if at the same time we reflect that this robbery may, and too often does, co-exist with the other causes which we have instanced as tending to clover-sickness, we should no more call land sick of clover because it will not bear this crop under our exhaustive system of cultivation than we should call a barren sand wheat-sick for refusing to grow corn. ANALYSES OF BARLEY AND CLOVER. +----------------------+-----------------++-----------------+ | | PLAYFAIR || WAY. | | +--------+--------++--------+--------+ | | Barley | Barley || Red | White | | | Grain. | Straw. || Clover.| Clover.| +----------------------+--------+--------++--------+--------+ |Silica | 28·97 | 46·30 || 3·34 | 3·68 | |Phosphoric acid | 35·68 | 3·22 || 6·35 | 11·53 | |Sulphuric acid | 1·22 | 2·61 || 4·18 | 7·21 | |Carbonic acid | | || 16·93 | 18·03 | |Lime | 3·06 | 7·59 || 35·39 | 26·41 | |Magnesia | 8·04 | 3·55 || 11·22 | 8·15 | | |and loss|and loss|| | | |Peroxide of iron | 1·94?| 4·35?|| 0·97 | 1·96 | |Potash | 15·61 | 22·17 || 14·85 | 14·33 | |Soda | 5·03 | 0·84 || 1·40 | 3·72 | |Chloride of sodium | 0·45 | 9·37 || 2·36 | 4·94 | |Chloride of potassium | | || 2·96 | | | | ------ | ------ || ----- | ----- | | | 100·00 | 100·00 || 99·95 | 99·96 | +----------------------+--------+--------++--------+--------+ We cannot better conclude this chapter than by quoting the following from Baron Liebig’s _Letters on Modern Agriculture_, so ably translated by Professor Blyth:—