As to the uranium in hokutolite, there is no analytical evidence, hitherto, of its presence in this mineral, and it is thought quite useless to calculate it from the amount of radium, as the mineral is obviously of the secondary nature. The radium- and thorium-contents of the two kinds of hakutoutes mentioned above are respectively of the same order and quite similar. The comparatively large content of radium, however, in comparison with the poorer content of thorium shows that the radioactivity of this mineral is mainly ascribed to radium and its disintegrating products and very little to the members of thorium-series. It is seen that the allanite from Shirakawa, Kyoto Prefecture contains 1.05% Th O2 and 0.017% U3O8. The uranium-content of the xenotime-portion of the xenotime-zircon from Ishikawa was determined to be 2.42% U3O8. According to K. Kimura(1), the average amount of uranium in the “ Kikukwa-seki” is said as being 1.92% U O2. These results indicate that the amount of uranium in the zircon-portion of the latter mineral is probably less than that in the xeno-time portion. In conclusion, the author wishes to express his hearty thanks to Dr. S. Iimori for his kind direction during the course of this experiment.
1. The amounts and the velocities of sorptions by partially dehydrated heulandite of ammonia, carbon dioxide and ethylene have been measured. 2. It was known that the heulandite absorbs only ammonia in considerable amount. 3. The number of mols of ammonia sorped are nearly identical with that of water evaporated in the process of dehydration. So the ammonia is considered to combine chemically with the dehydrated heulandite. The composition of the substance obtained in the present experiment is probably Ca2Al4Si12O32·4H2O·7NH3. 4. The amounts and the velocities of sorptions by dehydrated chabazites of carbon dioxide, ethylene and ammonia have been measured. 5. Chabazite absorbs carbon dioxide and ammonia rapidly, but ethylene slowly. 6. Chabazite absorbs hydrogen only in small quantity.