We may summarize the purposes of this investigation as follows: A report on this investigation was made to Dr. John H. Yoe of the University of Virginia in order to see what reactions he considered to be of analytical significance and should be further investigated. He considers only three to be of any practical importance. They are as follows: 1. 7A-Oleic Acid. Solubility of the alkaline earth salts of some higher fatty acids. 2. 69A- 2-Acetamino 6-Aminobenzo Thiazole. A colorimetric reagent for iridium. 3. 71A 2-Hydroxy 3-Nitro 5-Sulfobenzoic Acid. A colorimetric reagent for ferric iron. A further investigation of compound 71A, as a colorimetric reagent for ferric iron, reveals that the sensitivity of this reaction is not great enough for it to be of any practical importance, since we have reagents (2) for this ion that are several times more sensitive. Prospective reagent No. 69A for iridium is being further investigated by Mr. J. R. Noell (1). A report on 7A will be taken up in Part II of this thesis. 1. It has been shown that there is very little difference in the solubility of the same alkaline earth salt of stearic, oleic, linoleic, and linolenic acids in the solvents, water, benzene, absolute ethyl alcohol and ether. 2. It has been shown that there is very little difference in the solubility of the different alkaline earth salt of stearic, oleic, linoleic, and linolenic acids in the solvents, water, benzene, absolute ethyl alcohol and ether, and benzene. 3. The solubility of the alkaline earth salt of these acids increases slightly with unsaturation, but does not increase as the degree of unsaturation increases. / M.S.