Abstract
THIS mathematical work is a critical application of the theory of chance to the breaking down of radio-active atoms. Its discussion is mainly based on the experiments of Rutherford and Geiger. Scintillations were produced on a screen by polonium, and were counted over a succession of equal short intervals of time, and the intervals were classified by the number of them which showed either no scintillation or one or two or more. The experimenters found that their numbers agreed well with those predicted by the theory of pure chance, but they gave no criterion as to the closeness of agreement to be expected. The calculation of the “mean errors” is a simple matter, but in the comparison of such a series of numbers it is only likely that in a few of the cases the mean error should be considerably exceeded. Prof. Bortkiewicz therefore provides a single test for the whole experiment. He works out twelve cases, and concludes that the results are, on the whole, slightly closer to their most probable values than is predicted by theory. He suggests an experimental cause for this small discrepancy. He also discusses one of the experiments of Marsden and Barratt, who made their analysis by classifying the lengths of time between each two successive scintillations, and he concludes that the distribution is normal. In this case his test is not perfectly satisfactory, as it involves the use of quadrature and interpolation formulae, processes which would seem to be very unsuitable for problems of chance. In both types of experiment distributions can be contrived which pass his tests, and yet are in reality very improbable, but no doubt there are great mathematical difficulties in the way of deriving the true probability test. From his work we may conclude that the search for regularity, other than the regularity of chance, in the disintegration of radio-active atoms is not a hopeful quest.
Die radioaktive Strahlung als Gegenstand wahrscheinlichkeitstheoretischer Untersuchungen.
By Prof. L. v. Bortkiewicz. Pp. 84. (Berlin: Julius Springer, 1913.) Price 4 marks.
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D., C. Die radioaktive Strahlung als Gegenstand wahrscheinlichkeitstheoretischer Untersuchungen . Nature 92, 684 (1914). https://doi.org/10.1038/092684a0
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DOI: https://doi.org/10.1038/092684a0