G. Hinrichs on Spectral Lines. 355 
For Kirchhoff’s line 1834:0 he finds W=5040-0 from 18 de- 
terminations, gonging from 5039°3 to 5041-4, showing a range 
of 2°1 (page 326, 1. ¢.} 
For ate 6 he finds W=5165'8 from 13 determinations, 
ranging gr et 1 to 51668 or a range of nearly two of our 
units (page 8 
In peqovdanae herewith we found it impossible for — parts 
of the spectrum, to draw a straight line through the points de- 
termined according to Ditscheiner’s wave lengths as cha to 
Kirchhoff’s millimeters as abscisse; showing that the decimal 
of Ditscheiner could not be relied upon, and in a few instances 
even the Le was Baier We will now review the caleitum 
Spectrum, as given in our first article. In addition to the pre- 
ceding, I will anit the intensity as given by Kirchhoff, and 
K the oes on ig es ff’s millimeter scale. ow is obtained as 
according to the scale mentioned in §2. It was impossible to 
obtain reliable results by arithmetical interpolation, the small 
errors of observation thereby affecting the final result to a very 
great extent, while by proper drawing of the line the individual 
errors of observation were as good as eliminate 
§ 18. Calcium spectrum.—We will, as in our first article, con- 
sider each of the six principal groups separately. 
Grove I. d,—3:3. Near line G. 
I K WwW D t Ww’ E 
be gg60-7 dae 48220 0 
4b 2864-7 4308'8 6-5 2 4308°8 0 
4 2854°7 4303°2 3:3 1 4302°2 +1 
4c 2834-2 4299°0 42989 +1 
The intervals are just as given in the preliminary Jneeaige 
tion—and E is completely abe the errors of observation. 
Group II contains too few 
Group III, d,==1:16. Near ame 
I K 
Ww i Ww’ 
45 15331 52615 5261-48 +02 
45 15305 «52617 § 21 8 
4c 15302  5263°6 13-1 ~—«5 26380 — 20 
de 1528°7 5264°9 47 4 526496 —-06 
6c =—-1522°7 «= 269°6 5269°6 OU 
The scale used for this interpolation was three times the one 
= in §2; 1 mm. K was represente 
to prevent misunderstandings it must be remembered siksacith 
n order 
the rashid a millimeter, while Ditscheiner expresses his hia rowulte in mil- 
lionths of a millimeter. 
