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droxide should be limited to a slight excess over that necessary to produce an reaction Or the use Of barium hydroxide should be adopted. Acknowledgment The authors are indebted to E*R*Hervey for the photograph of the apparatus 'described in this paper.
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Literature Cited (1) Assoc. Official Agr, Chem., Official and Tentative Methods of Analysis, 4th ed., pp. 60-1 (1935). (2) Spies, J. R., IXD.ENQ.CHEM., Anal. Ed., 9, 46-7 (1937). (3) Spies, J. R., J. Am. Chem. Boc., 58, 2386-8 (1936). APPROVEDby the Director of the New York State Bgricultural Experiment Station for publication as Journal Paper No. 329.
Thallous Carbonate as an Acidimetric Standard EINAR JENSEN
H
AND
BAILLI NILSSEN, Universitetets Kjemislre Institutt, Blindern, pr. Oslo, Norway
AC and Kftmen (8) have suggested the use of thallous carbonate as an acidimetric standard, and Berry ( I ) has recommended it for standardizations of acids and potassium iodate. Without knowledge of these two papers, a thorough investigation of thallous carbonate was started with the purpose of establishing its suitability for standardizing acids, and is reported fully elsewhere (5). Some of the observations made command interest in this connection. With regard to preparation of the salt, the effect of thallous carbonate on glass appears to have escaped notice. It was found that only platinum vessels in recrystallizations will give pure thallous carbonate. Hac and KAmen have chosen the extraordinary way of providing the absence of copper, lead, and bismuth in the thallous nitrate used for the preparation, but testing the carbonate itself for only sodium and nitric acid, I n the case of sodium the sensitivity of the test was not established. Neither they nor Berry gives tests for purity applicable to an unknown sample of the carbonate. Having spectroscopically ascertained the sufficient purity of a sample, tests with and without the addition of the impurity show that the following tests will prove the absence of (
