304 
Transactions of the Royal Society of South Africa. 
c 
/ 
It would have been convenient to call this chromane," but unfortunately 
Kostanecki has used this name already to denote the anhydride of o-oxy- 
phenylpropylalcohol. I shall therefore name it provisionally "fuchsene,' 
which will indicate that it is the hydrocarbon of fuchsone. 
Its fundamental wave-length is found by multiplying that of benzaurine 
(its di-oxy-derivative) by the square of the ratio of the wave-lengths of 
benzaurine and aurine (tri-oxy-derivative), i.e. x — 553''^ -f- 534^ = 593. 
The ratio — ^j^^ ^^^^^ colour-factors, and is the para 
benzaurine 
(or y) hydroxyl-f actor, its value being 0-9657 ; and it is to be noted that it 
is assumed to be the same whether — OH replaces — H or : 0 is attached 
to fuchsene giving fuchsone. The theoretical wave-length of fuchsone 
(oxofuchsene or keto-fuchsene) if it were soluble in alkali would thus be 
A 593 X 0-9657 or X 572|- ; that of oxyfuchsone or benzaurine* (oxyoxo- 
fuchsene) is X 593 x (0-9657)^ or X 553 ; that of aurine (dioxyfuchsone or 
dioxyoxofuchsene) is X 593 x (0-9657)^ or \ 534. 
The next ratio is the para (or y) amino-f actor, the value of which is 
0-972. The calculated wave-length for " fuchsonimine " t (iminofuchsene) 
is X 593 X 0-972 or X 576, but X 430 was observed in alcohol, with two other 
bands (ratio 16 : 13 : 10), which is certainly abnormal, but if the series is 
really 22 : 19 : 16 : 13 : 10 the observed band, which would be about X 425 in 
16 
water, a screes well with — x 576. 
22 
The calculated wave-length for the diamino-derivative, which is the 
well-known Doebner's violet, is X 593 x (0-972)2 or 560^. The reading X 565 
in alcohol is on record, and it is to be noted that there is no ionisation in 
alcohol, so that the chlorine of the coloured salt counts as part of the 
* There appear to be two kinds of benzaurine. The one in the text, of X 553, is 
made from _p-oxybenzophenone and phenol, the other of X 570 (Part I, 1917, p. 6) from 
benzaldehyd and phenol with oxidation. These two reactions should give the same 
product, but the products are undoubtedly different. 
t This confusing name should be changed to fuchsimine. 
