Excitation functions for a number of C 12 -, N 14 -, and 0 16 -induced reactions on aluminum-27 have been studied using stacked-foil techniques and the ion beams of the Yale Heavy Ion Accelerator. The yields of CI 34 -38 , P 32 , Al 28 -29 , Mg 27 , Na 24 , and F 18 have been measured in the energy range from 10.5 to about 1 Mev per nucleon. The production of the radionuclides Cl 34 > 38 , P 32 , and in the case of C 12 irradiation Al 28 , are due to evaporation processes from a compound-nucleus system, while the production of F 18 , Na 24 , Al 28 , Al 29 , and Mg 27 seems to occur by a direct-interaction mechanism. A comparison of the yields for specific radionuclei produced by different beams is given.

Phys. Rev. 125, 606 (1962)]. The cross-section values listed in Table II and represented in Fig. 2 for the production of Al 28 from C 12 irradiations at 115-108.5, 108.5-102.5, and 102.5-94.8 MeV should read 70 mb, 81.2 mb, and 90.2 mb. The data still indicate that Al 28 is primarily produced via a compound nucleus mechanism with some contribution from a direct interaction process. Curie Point and Origin of Weak Ferromagnetism inHematite, A. AHARONI, E. H. FREI, AND M. SCHIEBER [Phys. Rev. 127, 439 (1962)]. The Curie point is in error. The DTA measurements show a second-order transition at 690°C. Mossbauer effect measurements of Hillman quoted in the paper were also revised. 1 The other transition is thus of no physical significance. The theory given might be applicable to some other substance but is, therefore, not relevant for a-Fe20 3 .