Colour and Chemical Constitution. 
309 
Although the acid bands are abnormally broad and of somewhat uncertain 
centre, I do not think that this fact fully accounts for the discrepancies 
of the above table, but admit that there is probably some factor not taken 
account of which modifies the action of the frequency-law. 
The abnormal colour of "crystal-violet" may next be considered : it has,^ 
of course, been the subject of active discussion for thirty-five years. 
The following table exhibits the results of my observations on the 
" aniline dyes " in presence of alkali and acid. It should be noted in regard 
to the mono-derivatives of fuchsene that fuchsone is insoluble both in acid 
and alkali, and that fuchsimine and its dimethyl-derivative are insoluble in 
alkali, but soluble, with colour, in acid, with bands at about \\ 430 and 460 
respectively. 
A. Di-derivatives of Fuchsene {all Para). 
Name. 
Substituents. 
Alkali A. 
Acid A. 
Notes. 
Benzaurine .... 
Aminofuchsone . 
Doebner's violet . 
Two OH 
One OH, 
one NHo 
Two NH2 
553 
558 
494 
? 
562 
Nearly neutral. 
Benzaurine .... 
Dimethylaminofuchsone 
Malacliite-green . 
Two OH 
One OH, 
one NMe.2 
Two NMe2 
553 
586 
494 
515 
broad 
619 
? 500 + 530 
Nearly neutral. 
B. Tri-derivatives of Fuchsene {all Pa7'a). 
Name. 
Substituents. 
Alkali A. 
Acid A. 
Notes. 
Anrine ..... 
Paeonin (aminobenzaurine) 
Eed corallin (Diaminofuch- 
sone) 
Pararosaniline 
Three OH 
Two OH, 
one NH, 
One OH, 
two NHo 
Three NHo 
534 
538 
541 
7iil in alkali, 
544 neutral 
485 
497 
? 
575 
Also 503 + 548, then 
neutral. 
Also 518 faint. 
Aurine ..... 
Dimetliylaminobenzaurine . 
Bis -dimethylaminofuchsone 
(oxymalachite-green) 
Crystal-violet 
Three OH 
Two OH, 
one NMe.i 
One OH,'' 
two NMe., 
Three NMej 
534 
575 
580 
nilin alkali, 
595 neutral 
485 
500 
607 
632 
Interpolated. 
We note that the normal colour is in alkali in OH-compounds, and in 
acid in amino-compounds, yet nevertheless the differences in colour are 
regular, e.g. 553, 558, 561: 553, 586, 619: 534,538,541,544: 534,575, 
