In the first series of eight determinations 23.3275 grams of cadmium bromide were equivalent to 32.2098 grams of silver bromide. If the atomic weight of silver = 107.93. ” ” ” ” ” bromine = 79.95. ” ” ” ” cadmium = 122.239. Maximum, 112.290. Minimum, 112.169. Where the difference between the maximum and minimum value is slight, the average of the separate determinations agrees closely with the number found by comparing the total substance used with the total product obtained. The latter method of calculation seems however to be preferable. In the second series of eight determinations 28.6668 grams of cadmium bromide were equivalent to 22.7379 grams of silver. Using the same values for silver and bromine, the atomic weight of cadmium = 112.245. Maximum, 112.320. Minimum, 112.180. The agreement of the separate determinations with each other is fairly close and the average of the two series of determinations is nearly the same. Huntington took great care in the purification of his material and in the carrying out of his method, which are strong arguments in favor of his work, yet his method is not as simple as could be desired where the nature of the work demands the greatest possible accuracy in all details and it also appears to be subject to some of the errors common to ordinary analytical operations. Partridge. Amer. Journ. Science XL, 377. 1890. Methods: 1ˢᵗ. Decomposition of the oxalate to the oxide. 2ⁿᵈ. Reduction of the sulphate to the sulphide. 3ʳᵈ. Conversion of the oxalate into the sulphide. As an average of the determinations made by each method Partridge gives: 1ˢᵗ series, atomic weight of cadmium = 111.8027. 2ⁿᵈ ” ” ” ” ” = 111.7969. 3ʳᵈ ” ” ” ” ” = 111.8050. An excellent agreement between results obtained by different methods[1]. That this very close agreement is only apparent has been shown by Clarke. He has found that the above calculations are based on the assumption that the atomic weight of carbon = 12, and that of sulphur = 32 when oxygen = 16. There seems to be little justification for this rather arbitrary selection by Partridge since the most refined work shows that whole numbers do not express the most probable atomic weights of carbon and sulphur in a system where oxygen = 16. [1] Amer. Chem. Journ. 13, 34. 1891. The atomic weight of cadmium calculated from the total material used and the total product found in each of the three series is: O = 16. C = 12. S = 32. At.Wt.Cd. 1ˢᵗ series, CdC₂O₄ : CdO = 12.66368g. : 8.10031g. 111.805. 2ⁿᵈ ” CdSO₄ : CdS = 15.93505g. : 11.02691g. 111.786. 3ʳᵈ ” CdC₂O₄ : CdS = 16.85228g. : 12.12906g. 111.806. difference, 0.020.