ELECTROMETRIC ESTIMATION OF MAGNESIUM 2243 pressure was constructed. Direct measurements of the eutectic pressure, and of the freezing pressure of a 10% solution, showed a fair agreement with the indirect determinations.

1. Data and curves are presented on the absorption spectra of various phthalein derivatives of pyrogallol, hydroxyhydroquinol and phloroglucinol. Correlations are drawn with data previously obtained for phthaleins of the mono-and dihydroxybenzenes.2. The effect on the chemical properties and absorption spectra of the phthaleins, due to the introduction of hydroxyl groups, is discussed.3. Gallein, which is colored in both the solid state and in neutral solution, is shown to be primarily lactoid in structure, but probably in equilibrium with a small amount of the quinoid modification. 4. The unusual behavior of hydroxyhydroquinolphthalein in weakly alkaline solutions both as regards its absorption and fluorescence is described and a possible explanation is advanced.

influence the relation between the degrees of dissociation of the zinc and the nickel salts respectively. Accordingly, two solutions were prepared, both fairly dilute, and differing not too extensively in the relative concentrations of the nickel and the zinc salts. T h e data for these solutions are :-(a) Solution same as for Series 4, except that the total volume of the solution is fifteen liters (i.e. three times as much as before). Witb current densities above two amperes the alloys obtained were practically of constant composition. T h e alloy obtained with C.D. = 3 amp. contained 4.6 per cent. nickel. Hence the ratio of zinc to nickel (by equivalents) in the alloy equals 5.4 times their ratio in the electrolyte.

r68 iv. 13. PRITZ. \. (; T I I , I , .~U D E~. ; z w 1 R WITHROW. when low humidity usually prevails indoors, and a t such times the difference in temperature between the water and the surrounding atmosphere may amount to 4' or more. It takes some time for the sample to attain the temperature of the water, if i t is drawn directly into the buret, and if accurate results are to be obtained with the original Pettersson-Palmqvist apparatus or with any of the forms mentioned under group 11, the manipulation cannot be continued until this condition has been satisfied. In many cases the movement o f the manometer liquid resulting from the change of volume due to thk cause alone is greater than would result from the removal of the carbon dioxide that the sample contains. The necessity for delay iq completely obviated when the sample is drawn through the copper coil. The apparatuc; is manufactured by Greiner and Friedrichs, Stutzerbach in Thuringen, Germany.

No abstract

The acid produced in this way will absorb a small amount of moisture if exposed to the air.The mother liquors, which are occasionally dark colored, may be readilyWe have shown the availability of zirconium sulfate as a reagent for potassium in the presence of sodium2 and ammonium.3 The less frequently occurring members of the fifth group, rubidium and cesium, both interfere with the detection of potassium by sodium cobaltic nitrite, perchloric acid or chloroplatinic acid. Lithium can be separated from ions of these elements by perchloric acid or chloroplatinic acid. Tread-1 The authors are indebted to the Chemical Department of this University in that Professor Marion Hollingsworth of the Analytical Chemical Division of that Department furnished the rubidium and cesium chlorides used as the basis of part of this work.

No abstract

No abstract