( 744 ) 
Agon Clan Discoloration in daylight 
Very fine grain (October 11 to 2 o’clock) 
In gelatine. 
(1) with 10°/, aqueous AgNO, sol. reddish orange 
(2) with AgNO, dry red. 
(3) with NH,Cl moist violet. 
(4) with NH,Cl dry blue. 
Without binding substance. 
(5) with NH,Cl under CCl, bluish green. 
By variation the amount of water all intermediate tints can be 
obtained between preparations (8) and (4), while by decrease of the 
amount of AgNO, preparation (2) becomes reddish violet to violet, 
and has for this reason been placed before (3). 
The preparations (2), (4) and (5) still contain a trace of adsorbed 
water. 
In Porrrvin’s photochromics there also occurs a yellow (more 
orange-like) subchloride. Preparation (1) already yields a colour 
which inclines from red to yellow; therefore the yellow subchloride 
is probably formed after the red. In direct sunlight this preparation 
assumed a yellow colour. However, | found no indications that this 
was a subchioride, for neither in ammonia nor in a 10°, sodium 
thiosulphate solution did it undergo any perceptible change, while 
the red and the reddish orange preparation became yellow and 
yellowish brown in these two solutions. So it may just as well be 
photo-chemically formed collodial silver. However, the yellow sub- 
chloride cannot be classed anywhere between or before the other 
colours. In analogy with what is similar in the case of the sub- 
bromides it may therefore be assumed, that after all, it comes after 
the reddish orange preparation. 
The green « subchloride is known to be the subchloride richest 
in halogen, and preparation (5) already inclines to it, so that in the 
case of the subchlorides the colour sequence of series (11) is 
green, bluish green, blue, violet, red, orange, yellow. . . (VI) 
The silver subjluorides. Silver fluoride is hygroscopic and too 
insensible to light for these experiments. Still there is a yellow sub- 
fluoride of Guntz **) with the formula Ag,Fl. 
The silver subcyanides. Their existence is still doubtful. A chemi- 
cally pure silver cyanide preparation of E. pr Hain, showed the 
same bluish violet discoloration both without and with a binding 
substance, and even under CCI, In the case of silver cyanide the 
‘photo-chemical decomposition Te takes place according to he 
laws than with the foregoing silver (sub)haloids. 
