The cadmium bromide was prepared by dissolving the carbonate in hydrobromic acid and subliming the product in a stream of carbon dioxide.
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: