Abstraet Sargent curves have been plotted for the isotopes of atomic numbers between 29 and 33 using the results obtained by us. The curves fit better to the Fermi's theory than K-U. The same results are also obtained in the study of Sargent curves for natural radioactive elements and for very light elements A fact, is also pointed out that. if the Sargent plots are made for all elements on the same diagram, a very clear front is produced A brief discussion for it is also given
4. Summary. The scattering cross sections of slow neutrons (" C " and " D" neutrons) were measured by the method of back scattering for several elements having large " C " neutron absorption cross section. The marked non-additivity in the scattering crows sections between Hg, HgS and S which was reported in a previous paper(8) was found to be in error. Both mercury and its compounds have a large " C " neutron scattering cross section as compared to the " D " neutron cross section. The scattering cress sections for silver and iodine were found to be independent of the neutron energy. The results are summarized in Table II. In conclusion, I express my sincere thanks to Professor S. Nishi- kawa for his kind guidance throughout this work, and to Professor T. Muto for his hearty encouragement. I also wish to acknowledge my indebtedness to Mr. S. Mizukami for his cooperation in this work in its latter stages. I am much indebted to the Japanese Foundation for Cancer Research for supplying the radon necessary for this work through helpful interests of Dr. II. Yamakawa and Mr. M. Miwa