i 
him in the sun’s chromosphere and also by Rayet in the 
1868, one of which may coincide with this fourth auro 
466 Scientific Intelligence. 
alone was absent. The measurements are exact to half a division 
of the scale. ‘ 
To determine the approximate waye-lengths of these lines com- 
parison was made both with certain elemental lines and with the 
lines of the solar spectrum. On the scale of this instrument, the 
elemental lines employed read as follows:— 
Ka63, Lia 79, Srf 80,H(c) 82, Caa 91, Sra 96, Caf 113, H(f) 146°, 
Srd 163, Cs6 165, Csa 167, Rba & f 200, Kf 218. 
The Fraunhofer lines measured as follows :-— 
a 70°5, B 76, C 82, D 100, E 124°5, 6 130, F 146°5, G 189. 
ments. In this way the wave-lengths of the five auroral lines 
were obtained as given in the following table :— 
Seale Wave- Auroral 
Line. number. length. lines. Other measurements. 
6 687 
Cc 82 656 
1) 90 623 623 627 Zoliner. 
100 589 
(2) 110°5 562 562 557 Angstrom. 
E 124°5 527 
(3) 130 517 517 520 Winlock. 
b 130 517 
(4) 138 502 502 
F 146°5 486 
®) 149 482 482 485 Alvan Clark, Jr. 
or 189 431 
In this table, column 1 gives the auroral and the Fraunhofer ae : 
column 2, the number of these as measured upon the scale of the J 
Spectroscope used; column 3 : 
3 
coal 
A 
g 
B 
@ 
er 
° 
5 
ot 
a 
© 
2 
Es 
=f 
‘3 
‘. 
i 
= 
az. 
ba 
: 
< 
Ne 
5 
o 
i 
ww 
h 
Cire ee ey 
New Haven, Nov. 13, 1871. 
