Abstract
Since the termination of the war a remarkable progress had been made in the methods of chemical analysis. Especially partial adoption of a physical process in place of a wet process could be regarded as one of the development. In the wet process personal elements enters so largely that accurate results are difficult to obtain. Rapid methods in conformity with the factory operation were under the control of time. According to the statistics, variation was usually big and the biased values frequently appeared. It is a matter of common knowledge that the cause of personal error lies in unskillfullness of workers. Nowadays, various methods concerning the error control have been given in academic journals.
1. Preparation of standard samples, then leaving the workers engaging in analysis uninformed the mixing of them among samples.
2. In practising this research, the sources of variation were designed so as to make as uniformly as possible, and the order of analysis was randomized.
3. Comments were given on the comparative results of analytical value determined by workers with the standard value and its rejection limits.
