100 YEARS AGO

I happened to possess a small sample of a red deposit, coloured by iron, which is left by the water of the King's Spring, at Bath. It occurred to me that it might be worth while to test this for radio-activity. The result was to show that the deposit was markedly active. On leaving it in the testing vessel (which was closed airtight) for a few days, the activity was found to increase to several times its initial value. This shows that the deposit gives off an emanation freely, even without heat. Experiments were then made to test the rate of decay of this emanation. It proved to be identical with the rate of decay of the emanation of radium.... The presence of radium in the Bath water and deposits is of special interest because of the occurrence of helium in the gas which arises from the spring... There can be little doubt that the helium owes its origin to the same store of radium that supplies the water.

From Nature 17 March 1904.

50 YEARS AGO

At a meeting of the Geological Society held at Burlington house on February 24, Mr. A. T. Marston exhibited a number of flints which he had attempted to stain with chromic acid or potassium dichromate in order to assist appreciation of the condition of the Piltdown flint recently described by Drs. Oakley and Weiner (Nature, December 12, 1953). Mr. Marston pointed out that though some types of these flints would not stain at all, others became deeply stained. In the latter case, however, the stain was very difficult to remove. As the stain on the Piltdown flint had apparently been easily removed by acid, Mr. Marston queried whether it had indeed been artificially produced, and also inquired whether there was any possibility that traces of chromium might exist naturally in the ferruginous Piltdown gravels. Dr. Oakley then exhibited specimens of flint from Piltdown, and described tests that had been made on all the flints illustrated in the original paper by C. Dawson and A. Smith Woodward. All these flints had a ferruginous stain which was easily removed by acid, in contrast to the other ‘natural’ flints from the Piltdown area collected at the same time... Dr. Oakley believed that the illustrated flints had been stained artificially with a ferruginous solution, and in one case a chromic solution had also been used in order to make the flint less red, and so resemble more closely the ‘natural’ flints.

From Nature 20 March 1954.