100 and 50 years ago

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    100 YEARS AGO

    ‘A Diagram of Heredity’ — Francis Galton.

    The law of heredity which was formulated by myself ⃛ and which, as I am exceedingly gratified to learn, is now strongly corroborated by an independent investigation, has recently been illustrated by a useful diagram. ⃛ The two parents between them contribute on the average one half of each inherited faculty, each of them contributing one quarter of it. The four grandparents contribute between them one quarter, or each of them one sixteenth; and so on, the sum of the series 1/2 + 1/4 + 1/8 + 1/16 &c. being equal to 1, as it should be. ⃛ The area of the square diagram represents the total heritage of any particular form or faculty that is bequeathed to any particular individual. It is divided into subsidiary squares, each bearing distinctive numbers, which severally refer to different ancestors. The size of these subsidiary squares shows the average proportion of the total heritage derived from the corresponding ancestors. ⃛ The Subject of the pedigree is numbered 1. Thenceforward whatever be the distinctive number of an ancestor, which we will call n, the number of its sire is 2n, and that of its dam is 2 n + 1. All male numbers in the pedigree are therefore even, and all female numbers are odd.

    From Nature 27 January 1898.

    50 YEARS AGO

    During a television outside broadcast from Brands Hatch, in Kent, during the afternoon of August 31, 1947, there appeared on the screens and from the loudspeakers of two television receivers ⃛ a sudden and intense increase of fluctuation noise. The visual effect was that of a violent snowstorm of the type well known to televiewers due to a motor-car ignition interference, but at a very much more intense level than seen heretofore by either of the observers. ⃛ It would seem beyond reasonable doubt that the interference observed was, in fact, solar noise, particularly when the radio of television band-width (5,000 kc./s.) to recording receiver band-width (about 20 kc./s.) is taken into account.

    From Nature 31 January 1948.

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