Some Spectroscopic Notes. 459 
Finally, the satellite system was obtained as in the vacuum 
tube (fig. 5). The results were :-— 
A B C ID) F 
—(0:227 —07106 —0°056 0°046 0:084 
Fic. 9 A. striking reversal effect (fig. 9) was 
- also obtained for the yellow line in the 
are. Ej was very faint; EH, is E in the 
_ next order. Measuring from a_ point 
midway between B and C we have 
E ABC DE AUB oF ashe 
‘4 —O14 —0°05 4+0°05 +016 +0°29 
The current varied from 5 to 7 amperes during the above 
measurements. 
Readings were also made on the lines of zine in the electric 
are. The zine was introduced into the are by boring the 
Jower carbon which was the anode, and packing strips of 
thin zine sheeting into the hole. Again some very striking 
forms of reversal were obtained. They did not maintain 
themselves so long as in the case of Hg, and passed out of 
the one form into the other frequently when I was making 
measurements on them. It was easier to recognize the zinc 
lines as being reversed. Changes took place in the reversal 
system when the arc began to hiss. Also the 
distance between the ditferent bands varied in 
the different parts of the arc, being greater and 
better defined near the anode A; being small 
but well-defined at the edges B, and being as 
a rule ill-defined towards C. 
Each of the four lines, the red and the three 
blue (6361, 4812, 4721, and 4681) reversed 
roughly speaking in three types, figs. 10, 11, & 12: Let 
Fig. 10. us take the measurements for the case of 
| | 4812, the bright blue line. Measuring 

the wave-length differences in the three 
cases from B, E, and L, we obtained 
Fig. 10. CC... +40°05 
a ae Big. 2h.) My; —0-06 
ae Fo Lows 
: Bis, 7. Gr... Ug 
| 4 H... —008 
MM... +0086 
testy 3 Pear oeie 
_ ‘Fig. 12. P may, however, be G in the next order. 
Using a different are-lamp and a 
| smaller quantity of Zn, I was able to 
| | get the lines without reversals. The 
G H Lm pred line (A=6361) was single. The 
