In making a further supply of the salt it was found that if the solution, after filtering from the barium carbonate, was diluted to such an extent that no crystals separated on cooling, then on slow evaporation under a bell-jar the first crystals to appear were very long slender needles. As evaporation proceeded, these needles became much thicker assuming prismatic proportions, and corresponded in appearance to the salt described by Hollis as having six molecules of crystal water. As growth proceeded, the crystals became dark in color, and the mother-liquor correspondingly clearer, the crystals evidently absorbing the impurity in their growth. When the solution had become quite colorless, rhombic crystals of the salt containing seven molecules of water of crystallization appeared. The larger prismatic crystals were carefully removed, and redissolved in water in order to see if the same phenomena would repeat themselves. This in fact was the case, crystals of both types appearing in the same way as described. Without separating the crystals in this second experiment, water was added, and the crystals dissolved. The solution was then warmed briskly with boneblack, and filtered. From the filtrate, which was colorless, nothing but rhombic crystals having seven molecules of water of crystallization could be obtained, although a great many variations in the conditions were tried. Analysis of these last crystals was as follows: 0.2400 gram lost 0.035 gram at 210°, and gave 0.0637 gram BaSO₄. Cal. for (C₁₃H₈O₆NS)₂Ba + 7H₂O. Found. H₂O = 14.40 14.58 Ba = 18.29 18.27 Hollis states that treatment with boneblack decomposes this salt, and hence he did not purify it prior to crystallization. From the experiments just described it seems probable that the impurities present affect the crystalline habit, and the degree of hydration of this salt in a very striking manner. By careful warming with boneblack no decomposition was observed, and the crystals so obtained have constantly seven molecules of crystal water. VI. The Action of Alcohols upon the Symmetrical Chloride of Paranitroorthosulphobenzoic Acid. Kastle[15] found that when the chlorides of paranitroorthosulphobenzoic acid (which he supposed to be an individual) were dissolved in alcohol, and the solution boiled for some time, the acid etherial salt of paranitroorthosulphobenzoic acid was the final product. The reactions were shown to be: COCl COOC₂H₅ / / I. C₆H₃——SO₂Cl + C₂H₅OH = C₆H₃——SO₂Cl + HCl. \ \ NO₂ NO₂ COOC₂H₅ COOC₂H₅ / / II. C₆H₃——SO₂Cl + C₂H₅OH = C₆H₃——SO₂OC₂H₅ + HCl \ \ NO₂ NO₂