ASTRONOMY: F. G. PEASE 
N F 
23 
« mi warn mmmntm mmtm * < 
m mm mumWMM® t«» *mt s 
»tm mm-mmm •* 5* **** * 
a ma rmmmm* R MM * ««•* *s 
itirt! * iSB»«*»«BS .'M <# * »«t« * - • 
S P 
FIG. 1. SPECTRUM OF THE CENTRAL PARTS OF THE ANDROMEDA NEBULA. EXPOSURE 79 
HOURS 
Km 
-420 
_ + += Measures along MAJOR AXIS 
380 
0= Measures along MINOR AXIS 
340 
300 
+ 0 0 - 
0 \_ + 
\. + 
NF 
150 120 90 60 -30" 0 +30" 60 90 120 
150 
VEL0CITY v CURVE OF THE ANDROMEDA NEBULA 1917 
FIG 2 
strengthen the conclusions derived from the latter by showing that the variable 
velocity given by the spectrogram first described is without doubt to be 
attributed to the rotation of the nebula. 
The arms of the cross in figure 3 indicate the length and position of the slit 
on the nebula. 
