Classification of inorganic chemicals: composition, not trade name, determines whether a product is treated as a fertiliser for tariff purposes. The Board clarifies that mono potassium phosphate, calcium nitrate and potassium magnesium phosphate as single chemically defined compounds are classifiable under Chapter 28, but mixtures or salts in which those compounds are constituents are classifiable under the Chapter for fertiliser mixtures; trade name does not determine classification and assessment must be based on actual product composition.