Magnetization and susceptibility data are presented for niobium rod samples in the temperature range of 1.2°–8.9°K. The niobium samples tested had a range of tantalum content from 700 to 4000 ppm. The samples were annealed and degassed in high vacuum at temperatures between 2100° and 2300°C. Values of &kgr;1, &kgr;2,Hc1,Hc2, andHcare presented as a function of tantalum impurity, and these values are compared with theoretical predictions.