A comparison of the geodetic reference levels of England and France by means of the sea surface

The magnetic susceptibility of a powdered specimen of caesium titanium alum has been measured at temperatures between 4$\cdot $2 and 1$\cdot $0 degrees K. The susceptibility is found to obey Curie's law, with a Curie constant 0$\cdot $118 per mole, corresponding to a Lande factor g = 1$\cdot $12. Measurements of spin-lattice relaxation effects between 1$\cdot $3 and 0$\cdot $9 degrees K give a relaxation time varying as T$^{-7\cdot 5}$. An approximate measurement of the specific heat at 0$\cdot $9 degrees K gives C$_{1}$T$^{2}$/R = 3$\cdot $9 $\times $ 10$^{-5}$. Interaction effects between the ions account for 90% of the specific heat, the remainder being attributable to the nuclear specific heat of the odd isotopes of titanium. The results are discussed in terms of the influence of the crystalline electric field on the energy levels of the magnetic ions.