Radium, and other radio-active substances : polonium, actinium, and thorium. With a consideration of phosphorescent and fluorescent substances, the properties and applications of selenium, and the treatment of disease by the ultra-violet light / by William J. Hammer.

  • Hammer, William Joseph, 1858-1934.
Date:
1903
Catalogue details

Licence: In copyright

Credit: Radium, and other radio-active substances : polonium, actinium, and thorium. With a consideration of phosphorescent and fluorescent substances, the properties and applications of selenium, and the treatment of disease by the ultra-violet light / by William J. Hammer. Source: Wellcome Collection.

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    Prof. Thomson was inclined to think that from the magnitude of loss found by Heydweiller, it must be due to some secondary effect, and he stated that he could not speak with certainty without a greater knowledge of the details of the experiments- As accounting for the results he, however, drew attention to the well-known coloration of glass by radium, by remarking, “One point, however, that ought to be attended to in these experi- ments is the effect of the radiation from radium on glass. Glass, as is well known, gets deeply colored when in contact with radium. It seems to me possible that the glass might be charged right through. If this were the case, it is possible that reactions might occur between the glass and the air, producing volatile substances and a loss of weight. I only throw this out with hesitation, for as I said before, I am not familiar with the details of the experiments.’’ Prof. Becquerel informed the writer that he knew nothing reliable regarding the experiments of Heydweiller, and called attention to his original paper on this subject which appeared in the Comptes rendus of March 26, 1900, adding, “I believe I am the first to have published an estimate in this way which could only result from my own experiments. The loss of one milligram per square centimeter requires one thousand million years. This statement refers only to the part of the deviable portion of the radiation to which measurements were applied; but this is only a part of the total loss. The deviable radiations comprise rays ranging from 109 and 3.1010 c.m. Besides, there is also all the non-deviable portion, either penetrating or absorbing, which corresponds to a notable loss of energy; and in addition, if the emanation is of material importance, which seems quite probable, the loss on this account would be a thousand times greater. These estimates are but theoretical, for it is probable that at least a portion of the mass calculated or estimated as material is apparent and corresponds to the effects of induction. ” In response to an expression of view from Sir William Crookes on a theory to satisfactorily account for the phenomena of radio- active substances, he wrote as follows: “You will find them fully given in my address to the British Association at their Bristol meeting in 1898. I have not seen any special reason to alter the views there propounded”; and in writing on the sub- ject of Heydweiller’s experiments, Prof. Crookes says, “I do not think the experiments of Heydweiller have been corroborated by other observers; and there are many sources of error in his