724 
PROFESSOR J. K LOCKYER ON THE PHOTOGRAPHIC 
The dividing' line between C4roup IV. and Group V. may very conveniently be taken 
by the absence or presence of the blue line of calcium at X 4226'G, this line makina 
its first apjDearance in the stars of Table A, Sub-division /3. 
We have then the following relation to the tables :— 
Table A, Sub-division y, 1 
5 J 
? 5 
5? 
55 
7 ’ 
8 
2 h 
Group IV, 
The Descending Series. 
If we treat the descending series in the same way, accepting the original definition 
of Group V., we have tlie following relation :— 
Table A, Sub-division y, 2 
Table A, Sub-division y8, 1'' 
J) 5) 2 
„ A3 )> Group V. 
M B, „ A 1 I 
„ „ A 2 J 
Here again, the photographs, so far as they go, fully justify the grouping suggested 
by the meteoritic hypothesis. 
Combining the two series, we thus get exactly the same order from the photo¬ 
graphic spectra, as that originally deduced, on the hypothesis, from eye observations. 
(4.) Extension of the Original Classification. 
Formation of Sub-groups. 
These considerations enable us to jirovisionally extend the classification originally 
suggested by the eye observations, as there are now many more details at our 
command. Further sub-division into species was attempted in the case of Group IL, 
and Group I. was divided into the two well-defined sub-groups of nebulae and bright- 
line stars. In the case of the other groups, a finer division was not possible from the 
available facts. 
Group II. was originally divided into fifteen species from a consideration of the eye 
observations. Since the photographs oyien up the blue for our investigation, the 
sub-division may be based on extent of the fluting-absorptlons in the way whicli will 
be indicated. 
Taking the groups in order, perhaps the most useful sub-division will be as indi¬ 
cated below. 
