I. II. Water 14.49 25.39 Sulphate of ammonia 62.55 47.79 Muriate of ammonia 15.3 ... Sulphate of soda ... 9.12 Sulphate of magnesia ... 18.38 Chloride of potassium 4.75 2.94 Chloride of sodium 17.35 0.35 ------ ------ 100.00 100.00 Ammonia 16.50 11.28 The quality of sulphate of ammonia may generally be judged of from its dry and uniformly crystalline appearance, and it may be tested by heating a small quantity on a shovel over a clear fire, when it ought to volatilize completely, or leave only a trifling residue. Some care, however, is necessary in applying this test, as in the hands of inexperienced persons it is sometimes fallacious. The salts of ammonia may be applied in the same way as guano; but they are most advantageously employed as a top-dressing, and principally to grass lands. In this way very remarkable effects are produced, and within a week after the application, the difference between the dressed and undressed portions of a field is already conspicuous. Experience has shewn that success is best insured when the salt is applied during or immediately before rain, so that it may be at once incorporated with the soil; as when used in dry weather little or no benefit is derived from it. It seems also to exert a peculiarly beneficial effect upon clover; and hence it ought to be employed only on clover-hay, as where ryegrass or other grasses form the whole of the crop we have better manures.