This investigation was undertaken for the purpose of determining whether the final product obtained in the analysis of uranium by Patera's method' was correctly represented by the formula Ka0(U2OJ2. In this connection it was also thought advisable for purposes of comparison, t o prepare pure sodium uranate and analyze it. both in the ignited and air-dried condition. The literature of uranium, while replete with analyses of the crystallized uranates of sodium and potassium, contains very little

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... uantitat i v work on the amorphous uranates of these metals, or such as are precipitated from uranyl solutions by the addition of sodium or potassium hydroxides. The results obtained by Zimnierman2 and Ditte,3 who prepared crystalline ?;a,U,O, and K2U,07 in the dry way, appear to have been applied directly to the amorphous compounds, as agreeing with the few analyses previously made of the latter. These early ana lyse^,^ howe~er, appear to have been of little value, for, as none of the analysts mentioned the great difficulty of completely washing out the alkali from the uranates, i t is reasonable to consider that this point was overlooked, and the results therefore showed a high value for sodium. The authors have observed that this analugy between the crystallized and amorphous uranates does not hold when the excess of alkali has been entirely washed out, as the results given below will show. Patera's method' for the determination of uranium is as follows: The uranium. in solution as nitrate, is separated from iron, aluminum, rnanganexe, zinc, calcium. etc., by treating \vith an excess of sodium carbonate solution, and boiling so as t o completely dissolve the double carbonate of sodium and uranium. After acidifying arid boiling o u t the carbon dioxide, the filtrate is treated with an excess of sodium hydroxide, and the precipitate washed it few times with hot water. After drying, the precipitate and the filter are separately ignited at redness in a platinum crucible, and then transferred to n snlall filter, where they are washed free from any remaining soda. The residue is then dried and reignited a t redness, after which, according to Patera. the composition is S a 0 The analytical behavior of thallium salts toward the electric current has been the subject of investigation by Schucht,' HeibergZ and N e~m a n n .~ The former used a nitric acid solution but the separation Berg. und Hiittenzeitwng, 39, 122 (1880). Chem., 35, 346 Ber., 21, 356. anorg.