Radiation measurement techniques of the early years, for both X-rays and radium, are not surprisingly linked with the early proposals for radiation units, although in certain instances the techniques were far from accurate and informative and occasionally bordered on the impractical, such as the suggestion by Pullin and Wiltshire in 1927^ that 'the depilatory property of X-rays is most remarkably constant in its effect and should be used as a method of measuring dosage.’ They did, though, recognise the ' obvious disadvantage of making the necessary observations on a human subject’ and suggested using mice instead. There was also a commercial aspect entering into radiation measurement in 1907 when Kassabian of Philadelphia^ was discussing units based on the ionisation effect. He suggested that 'an absolute unit could be the Becquerel or the Curie, while a commercial unit might be known as one ray.’