( 747 ) 
In the simplest case all the colours that appear, inclusive of the 
green of the a-subhaloid, may be reduced to 4 different ones, with 
the subhaloids belonging to them. If these subhaloids are indicated by 
the letters a, 3,y, and d respectively, then series (II) becomes : 
AgonHalon SAgenHalen—1 SAgenHalon—2 SAgenHalon—3 SAgonHalon—s >2nAg.(VII) 
z-subhal. B-subhal. y-subhal. 3-subhal. 
(green) (blue) (red) (yellow). 
in which 
Agon Halon—s = Agon Hal, 
or 
2n-—4 =n 
nis 4 
so that series (VII) becomes: 
Ag, Hal, — Ag, Hal, — Ag, Hal, — Ag, Hal, — Ag, Hal, — 8Ag. 
a-subhal. g3-subhal. y-subhal. d-subhal. 
(green) (blue) (red) (yellow) 
To summarize we may place the different subhaloids in the follow- 
ing table, in which Guntz’s solid subfluoride may very well be classed. 
subhaloid subiodide subbromide subchloride subfluoride 
a-(green) Ag, Ag,Br, Ag,Cl, unknown 
>-(blue) Ag.J, Ag,Br, AgCl, Ee 
y-(red) Ag,J, Ag,Br, Ag,Cl, 2 
d-(yellow) unknown Ag,Br, Ag,Cl, Ag, FI, 
- 
The g-subiodide (Ag,J,) has been inserted in this table, because 
the solarization and Herschel’s effect in the case of silver iodide plates 
point to the existence of this subiodide. 
In conclusion I wish to point out that I *) have only partly 
succeeded in observing the high sensitiveness to light of the a-subio- 
dide. The grey discoloration of the green preparation, which, as was 
shown by the sodium thiosulphate reaction, is caused rather by silver- 
oxide than by subiodides poorer in halogen, resp. silver, can hardly 
be ascribed to the formation of the blue g-subiodide, but may be 
put down to the formation of the red y-subiodide. 
If moreover, the regressive reaction by oxidation is taken into 
account, which, it is true, is less than in full daylight, but all the 
same has not been neutralized, the a-subiodide appears to be still 
far more sensitive to light than described by me. 
