Much work has been done in America, on the Continent and in this country, to determine the effect of different finely-ground naturally-occurring phosphatic substances on plants of various natural orders, grown under differing conditions as to the character of the soil and the use of other nutrient substances. In a few cases results or conclusions appear to conflict. Not nearly so much attention has been devoted to the effect of artificially prepared insoluble salts of phosphoric acid on the growth of plants. When these are employed in the absence of ammonium salts, and acid soil substances, definite information should be obtained as to the powers possessed by plants themselves of utilizing insoluble phosphates. With the object of making a contribution to such knowledge, oats, peas and swede turnips were grown in artificial soils made up of white sand and pure chalk, and the particular salt of phosphoric acid under investigation. The other essential nutrient substances were supplied in a dilute solution of salts.