Notes

Abstract

THE council of the Röntgen Society has now decided to act upon the advice of the committee appointed in 1906 to consider the possibility of preparing a standard for the measurement of radio-activity. This committee recommends that “The γ-ray ionisation from 1 mg. of pure radium be regarded as a standard, and called a unit of radio-activity.” The council has deputed Mr. C. E. S. Phillips to prepare a set of three substandards of RaBr₂, and these are now maturing. By the kind cooperation of Prof. E. Rutherford, comparison will be made with a specimen of the purest RaBr₂ at the Victoria University, Manchester. The quantity of radium in other specimens will be capable of accurate measurement by comparison with the substandards. It is anticipated, therefore, that by this means the exact description of medical, physical, or other work with radium will be facilitated, and that the possibility of fraud in the sale of expensive radium preparations will be eliminated. The council proposes to lend the substandards to any competent person desiring to measure the amount of radium in his possession, or to arrange for authoritative tests to be made. For further particulars application should be sent to the honorary secretary of the Röntgen Society, at 20 Hanover Square, London, W.