- Email: [email protected]
A new assay balance
386
CURRENT TOI'ICS.
[J. F. I.
A New A s s a y Balance. ANON. (Metallurgical and Chemical Engineering, vol. xiii, No. 8, August, I915.)--An assay balance operated like a typewriter is a novel development in scientific instruments. This balance is the invention of Mr. Wilfrid Heusser, of Salt Lake City, Utah. The feature of the instrument that marks a distinct advance in balance construction is the method of handling the weights, placing them on or removing them from the pan hanger. :By merely pressing one or more keys which are in front of and outside of the balance case, any weight or combination of weights can be deposited on the pan hanger. The weights themselves consist of perforated disks made of aluminum for the lighter and platinum for the heavier weights, as is usually the case. Normally each disk is carried by one of a series of upright posts with conical tops passing through a perforated horizontal frame which forms a part of the pan hanger. Each of these upright posts is operated by an individual key on a keyboard in front of the balance. By this means all handling of weights is avoided. An analytical balance embodying the Heusser construction as to truss beam and metallic case has also been developed. The Relation b e t w e e n U r a n i u m and Radium. F. NODDY and A. F. R. HITCHINS., (Philosophica~ Magagine, vol. 3o, No. 176, August, I915.)--The continuation of the measurements on the growth of radium from purified uranium preparations has shown an unmistakable increase in the rate of growth of radium in the case of the preparation containing three kilogrammes of uranium. The growth of radium appears to be proceeding according to the square of the time as theory requires, if ionium is the only long-lived intermediate member of the series. There is thus now for the first time direct experimental evidence that uranium is the ultimate parent of radium. The period of average life of ionium, calculated from this experiment, is about Ioo,ooo years, assuming 2375 years as the period of radium. An earlier preparation, containing 4o8 grammes of uranium, gives practically the same value for the period of ionium, calculated on the assumption that ionium was initially absent. The effect of any ionium initially present in the preparations would be to lengthen the period of ionium, but IOO,ooo years is probably not far from the actual period of average life.
¢ PRESS OF ~. B. L I P P I N C O T T C O M P A N Y PHILADELPHIA
CURRENT TOI'ICS.
[J. F. I.
A New A s s a y Balance. ANON. (Metallurgical and Chemical Engineering, vol. xiii, No. 8, August, I915.)--An assay balance operated like a typewriter is a novel development in scientific instruments. This balance is the invention of Mr. Wilfrid Heusser, of Salt Lake City, Utah. The feature of the instrument that marks a distinct advance in balance construction is the method of handling the weights, placing them on or removing them from the pan hanger. :By merely pressing one or more keys which are in front of and outside of the balance case, any weight or combination of weights can be deposited on the pan hanger. The weights themselves consist of perforated disks made of aluminum for the lighter and platinum for the heavier weights, as is usually the case. Normally each disk is carried by one of a series of upright posts with conical tops passing through a perforated horizontal frame which forms a part of the pan hanger. Each of these upright posts is operated by an individual key on a keyboard in front of the balance. By this means all handling of weights is avoided. An analytical balance embodying the Heusser construction as to truss beam and metallic case has also been developed. The Relation b e t w e e n U r a n i u m and Radium. F. NODDY and A. F. R. HITCHINS., (Philosophica~ Magagine, vol. 3o, No. 176, August, I915.)--The continuation of the measurements on the growth of radium from purified uranium preparations has shown an unmistakable increase in the rate of growth of radium in the case of the preparation containing three kilogrammes of uranium. The growth of radium appears to be proceeding according to the square of the time as theory requires, if ionium is the only long-lived intermediate member of the series. There is thus now for the first time direct experimental evidence that uranium is the ultimate parent of radium. The period of average life of ionium, calculated from this experiment, is about Ioo,ooo years, assuming 2375 years as the period of radium. An earlier preparation, containing 4o8 grammes of uranium, gives practically the same value for the period of ionium, calculated on the assumption that ionium was initially absent. The effect of any ionium initially present in the preparations would be to lengthen the period of ionium, but IOO,ooo years is probably not far from the actual period of average life.
¢ PRESS OF ~. B. L I P P I N C O T T C O M P A N Y PHILADELPHIA