29% 
1878.] fChase, 
prominent lines. The wave-measurements, in all of the following com- 
parisons, are taken from the paper of Professor Wolcott Gibbs, in the Ameri- 
can Journal of Science, second series, vol. xlvii, pp. 198, seq. Kirchhoff’s 
lines are indicated by K; Huggins’s by H; Gibbs’s groupings of corres- 
ponding lines, in the observations of both Kirchhoff and Huggins, by K H ; 
the left-hand columns containing Kirchhoff’s estimates, and the right-hand 
columns those of Huggins : 
Mercury, K H. 
Wave-lengths. Quotients. Theoretical. 
568.47 568.55 1.0000 1.0000 1.0000 1 
546.338 546.18 1.0407 1.0411 1.0406 1+ 6a 
542.80 542.80 1.0473 1.0484 1.0474 1+7a 
Hap, KO: 
Wave-lengths. Quotients. Theoretical. 
561.29 561.46 1.0000 1.0000 1.0000 1 
537.71 5387.85 1.0489 1.04389 1.0440 14+ 34a 
439.07 488.938 1.2784 1.2792 1.2784 1+194 
LiITHIuM, H. 
Wave-lengths. Quotients. Theoretical. 
610.73 1.0000 1.0000 1 
479.48 1.2277 1.2214 1+ 2a 
459.98 1.38279 1.3321 1+3 
RUTHENIUM AND IrR1IpIvuM, K. 
Wave-lengths. Quotients. Theoretical 
635.45 1.0000 1.0000 Ht 
545.44 1.1650 1.1646 1+ 5a 
530.52 1.1973 1.1975 1+ 6a 
CHROMIvuM, K. 
Wavye-lengths. Quotients. Theoretical. 
541.35 1.0000 1,0000 1 
521.20 1.0387 1.0887 1+ 1lla 
520.98 1.0391 1.0391 1+ 1124 
520.83 1.0394 1.0394 14 115 a 
CorpEr, K., 
Wave-lengths. Quotients. Theoretical. 
578.67 1.0000 1.0000 il 
529.30 1.0933 1.0914 1+64a 
522.24 1.1070 1.1066 1+7a 
465.64 * 1.2428 1.2437 1+ 164 
PROC. AMER. PHILOS. soc. xvilI. 101. 2K. 
PRINTED MARCH 27, 1878. 
