You will see from the table, that the plot which had the superphosphate, potash, etc., the year before, gives a peck _less_ wheat this year than the other plot which had none. Practically, the yield is the same. There is an increase of 13 bushels of wheat per acre--and this increase _is clearly due to the ammonia-salts alone_. The next plot was also a splendid crop. “What have you here?” “Superphosphate and ammonia.” This plot (11_a_), turned out 35 bushels per acre. The next plot, with phosphates and ammonia, was nearly as good. The next plot, with potash, phosphates, and ammonia, equally good, but no better than 11_a_. There was little or no benefit from the potash, except a little more _straw_. The next plot was good and I did not wait for the question, but simply said, “ammonia,” and the next “ammonia,” and the next “ammonia.” --Standing still and looking at the wheat, my father asked, “Joe, where can I get this ammonia?” He had previously been a little skeptical as to the value of chemistry, and had not a high opinion of “book farmers,” but that wheat-crop compelled him to admit “that perhaps, after all, there might be some good in it.” At any rate, he wanted to know where he could get ammonia. And, now, as then, every good farmer asks the same question: “Where can I get ammonia?” Before we attempt to answer the question, let us look at the next year’s experiments.--The following is the results of the experiments the _seventh_ year, 1849-50. Experiments at Rothamsted on the Growth of Wheat, Year After Year, on the Same Land. Table VII.--Manures and Produce; 7th Season, 1849-50. After the Harvest of 1849 the Field Was Tile-Drained in Every Alternate Furrow, 2 to 3 Feet Deep. Manures and Seed (Red Cluster), Sown Autumn, 1849. Manures FM Farm-yard Manure. P-A Pearl-ash. S-A Soda-ash. SMg Sulphate of Magnesia. B-A Bone-ash. SAc Sulphuric Acid. (Sp. gr. 1.7) MAc Muriatic Acid. SAm Sulphate of Ammonia. MAm Muriate of Ammonia. RC Rape-cake.