100 YEARS AGO

The recent tube operations in London have brought to the surface specimens of the London Clay from different districts. Samples of this clay taken from such different points as Hyde Park Corner, Brompton Road, and Haverstock Hill have been tested in the physical laboratory of the South-western Polytechnic for the presence of a radio-active gas by Mr. H. Cottam, and he has been unable to detect with his apparatus any marked quantity of active gas from the clays. With the same apparatus he has detected quite easily the radio-active gas from the water of a deep well... which goes below the clay to the greensand. We have come to the conclusion that the London Clay forms a floor through which the radio-active gas does not penetrate; or it may be said that the radio-active substance only travels when the water with which it is associated can travel. This is an argument in support of Prof. J. J. Thomson's view, that the radio-active gas, which he found in deep well waters, arises from the splitting up of a trace of soluble radium salt which comes up with the water.

From Nature 6 October 1904.

50 YEARS AGO

Little more than a hundred years have passed since hunters such as Gordon Cumming were at their work among the vast herds of big game in the southern quarter of Africa, and little more than fifty since Selous was making a living by ivory hunting somewhat farther to the north. All those countless thousands of animals have now disappeared for ever... The opening-up and white settlement of East Africa did not come until later, but although the same process of decimation began, and many parts of the country have been cleared of game, it is still possible to see great herds of wild animals that recall the accounts of conditions in South Africa given by the early travellers. Nevertheless, the presence of enormous herds of game animals is quite incompatible with the economic exploitation of the country and the rapid expansion of the native population; the game must go, and there can be no hope of its survival outside the National Parks and game reserves... As yet, however, there is practically no information available on the biology of these mammals, information that is essential for successfully managing such parks and reserves.

From Nature 9 October 1954.