The V iv spectrum has been extended by using as light sources a condensed spark and a hollow cathode discharge. With the new data, the experimental interpretation of levels of the 3d 2, 3d 4d, 3d 5s, 3d 5p, 3d 4f, 3d 5d and 3d 6s configurations has been completed with the exception of three levels of the 3d 4f and 3d 5d configurations. Four levels of the 3d 5g electron configuration have also been found. These levels account for 340 of the 360 lines assigned to V iv in the region 675 Å-5940 Å. Three members of the 3d ns series give an ionization potential of 376730 ± 40 cm-1 = 46.70 volts. The 4d 2D term of V v has also been located in the course of this work. With the aid of the new observations between 675 Å and 2200 Å the value of some levels already known has been improved.
Keywords: Atomic spectra; V iv and V v spectra; spectra; V iv and V v spectra; vanadium; V iv and V v; classified lines; V iv and V v; terms; the tourth and fifth spectra of.