  We have made an extensive study of the magnetic and electrical properties of
double-hexagonal closepacked NpPd3 and a range of U(1-x)Np(x)Pd3 compounds with
x=0.01, 0.02, 0.05, and 0.50 using magnetization, magnetic susceptibility,
electrical resistivity, and heat capacity measurements on polycrystalline
samples, performed in the temperature range 2-300 K and in magnetic fields up
to 9 T. Two transitions are observed in NpPd3 at T=10 and 30 K. Dilute Np
samples (x<0.05) exhibit quadrupolar transitions, with the transition
temperatures reduced from those of pure UPd3.
