The luminosity function for the globular cluster M3

. The luminosity function for M3 has been obtained from Mp = - 3.0 to Mp = +6.8 from counts on plates taken with the 200-inch Hale telescope. The counts give a total of 44,500 stars within 8' from the center of M3 brighter than m = 22.5, Mp = +6.9. The function has been carried to sufficiently faint magnitudes so as to include all stars which contribute appreciably to the total light. Ninety per cent of the total light of M3 comes from stars brighter than Mp = +3.8. The major contribution to the total mass comes, however, from stars too faint for observation. If the van Rhijn luminosity function, valid for the solar neighborhood, is used to extrapolate the M3 luminosity function, a total mass of 1.4 X io solar masses is found. This is a factor 4 smaller than the mass for M3 estimated from 0. C. Wilson's dynamical mass for the cluster M92. The uncertainty in Wilson's value prevents definite conclusions as to the validity of the discrepancy. If it is real, the globular-cluster luminosity function differs from the van Rhijn function at the faint end by a large factor. Evidence for a difference in the luminosity function for E nebulae and globular clusters is shown from the energy distribution curves in Figure 4. This indicates that globular clusters and elliptical nebulae are not scale models of one another.