ON THE ACTION OF LIGHT UPON DYED COLOURS. 353 
Induline Colours. 
Acid Colour. 33. Fast Blue 6B for wool. A sulphonated induline. 
Notre.—That Gentiana Blue 6B has proved to be fast is very remark- 
able, since the basic colours, and particularly those of the triphenyl- 
methane group, are usually so fugitive. During the first fading period 
the bloom of the colour disappears, but the remaining colour fades very 
little even throughout the period of a whole year. 
Crass V. Very Fasr Conours. (Woot.) 
The colours of this class show a very gradual fading during the dif- 
ferent periods, and even after a year’s exposure a moderately good colour 
remains. 
Oxazine Colours. 
Wool Book X. 
Mordant Colour. 6. Coelestine Blue B (Cr). Constitution not published. 
Thiazine Colours. 
Mordant Colours. 10. Brilliant Alizarin Blue R (Cr). Constitution not published. A 
derivative of oxy-naphtho-quinone-imide. 
i 12. Brilliant Alizarin Blue G (Cr). Constitution not published. 
Oxyketone Colours. 
Mordant Colours. 2. Alizarin Blue WX (Cr). Di-oxy-anthraquinone-quinoline. 
8. and J. 255. 
3. Alizarin Blue S powder (Cr). Sodium bisulphite compound of 
Alizarin Blue. §. and J. 256. 
# 4, Anthracene Blue WR (Cr). Hexa-oxy-anthraquinone. 
8 
. Alizarin Cyanine R (Cr). Penta-oxy-anthraquinone. §S.and J. 
249. 
_ 11. Alizarin Cyanine G (Cr). Action of ammonia on intermediate 
product in making Alizarin Cyanine R. S. and J. 250. 
es 13. Anthracene Blue WG (Cr). Constitution not published. 
os 15. Alizarin Indigo Biue SW (Cr). Sodium bisulphite compound 
of tetra- and penta-oxy-anthra-quinolin-quinone-sulphonic 
acid. 8S, and J. 257. 
Re 16. Alizarin Cyanine Black G (Cr). Constitution not published. 
Natural Colouring Matters. 
Direct Colour. 1. Vat Indigo Blue.» 
Additional Colowring Matters. 
Acid Colour. 2. Prussian Blue. 
Nores.—The great fastness of the Brilliant Alizarin Blues is remark- 
able, since they belong to a group of colouring matters which has not hitherto 
furnished fast colours. The same remark applies to Ccelestine Blue, 
although this colour is not so fast as the foregoing. The fastness of the 
various Alizarin Blues (oxyketone colours) is proverbial, and along with 
the colours just named they may well be regarded as worthy competitors of 
indigo for the production of fast blues. The chief difference of behaviour 
of Indigo Blue and some of the Alizarin Blues is that the latter tend to 
acquire a reddish tint, whereas the former does not. 
The remarkable fastness of Prussian Blue on wool is such that the 
1896. AA 
