An analy s is of Ni II based on 4300 obse rv ed lin es is prese nt e d. Th e low s tru c tures are 3d", 3d8 4s a nd 3d' 4s' whi c h a re now c omplet e exce pt for 3d 8 ( 'S)4s 'S and 3d' 4s ' ' 1',/, a nd th e higher of the two ' 0 te rill s of 3d' 45 '. Long se ri es occ ur suc h as 3d 8 45 to 95, 4d to 8d, 4/ to 7/, 5g to 7g. The analysis also in clud es Illany te rm s of th e co mplex s tru c ture 3d' 45 4p but o nly 55 per ce nt of the le vels within reac h of th e hollow ca th ode so urce have bee n found. Th e id e ntifi cation of the leve ls of 3d" 4d and 5d was a ss is ted by th e ca lc ulation s of N. Spector. Th e 4d' 4s ' leve ls were cal c ulated by Y. S hadm i, who a lso provided ca lcul ated positions for a ll th e le ve ls of 3d' 45 4p without whi ch mu c h of th e ana lys is would have bee n imposs ibl e. Th e 3d" n5 and 3d" nd se ries give a limit of 146532.0 but th e 3d 8 nK se ries giv es 146541.56. Th e latte r ha s be e n adopt ed t ho ugh no explanati on of t he di sc re pan cy has bee n found. Ke y word s : En e rgy levels; ioniza ti on pote nti a l; ni c ke l; spec tra l se ri es; spec trosco py ; wave le ngth .

No abstract

An analys is of Cu III based on o bservati ons from 500 to 6900 A is prese nte d . The low struc tures 3d 9 an d 3d B 45 a re comp le te , inc! udin g th e rare ly, if e ve r before , found 3dB (IS )45 2S. Th e 3d' 4s2 includ es 'F, ' F , 'C, and 2H but th e 'P, 2P, a 2 0 , b 20 have e lud ed all atte mpts to find th e m. Th e ionizat ion pote n· tial calc ulated from 45 , 55 , 65 'F.'/2 is 296980 c m _ 1 but by a comp arison with Ni II whi c h ha s a lo nge r series a n approx im ate valu e of 297 140 ca n be estimated . Th e 3d"4d gro up is co mpl e te, e xce pt for one leve l, as is 5d base d on 3F and IG , the oth e r 5d groups bein g in co mplet e. 3dB(3F)4fis co mple te a nd 26 le ve ls based o n 10, 3P , IG are kn ow n. 3dB(3 F )5g is in c omple te and a fe w le ve ls base d o n 10 a nd IG have bee n fo und. A di sc ll ss ion of th e validity of th e analysis of C u I V by 1. F. Sc hrode r a nd Th. A. M. Va n Kl eef is giv e n.Key wo rds : Atomi c e nergy levels; atomi c s pectrum ; copper; do ubl y ionized coppe r ; e lec tro n co n· fi gurati on; io nizati on potential; wavelength s.

It is shown that Takamine's new 3 iV level in Hg I is probably the lowest level from the structure d 9 s 2 p. The positions of the other levels are discussed and it is shown that some of them will be negative. The phenomenon of auto-ionization is described and its effect on the negative terms is suggested as the cause for the existence of ultraionization potentials. Some remarks are made regarding perturbed series.

The spark spectrum of silver can be based on a set of terms as follows: d D, 1 D from the structure 4^955; 3 &!P, D', FitomU^p^D, W from4d 9 6s; 3&1 5, P', D, F',G from 4i 9 5<2. The theoretically lowest term 1 S Q (4d 10 ) has not been found, but an estimate of its position is given. There is evidence also for the structure 4d 9 4/. All terms have intervals very different from the Lande values. The g-values also are evidently very irregular.The separate limits calculated from the Z D, l D series of two members show the same apparent divergence from theory as in Cu II, Ni I, Pd I. The intervals in the set 4d 9 5d also indicate divergence from theory. The calculated ionization potential is 17.1 volts from 5s 3 Dz.