Colour and Chemical Constitution. 69 
(26) Dioxyacridine. — This can be written in four ways and calculated 
from either of the hydrated forms, viz. : 
ho /\ / i N Xx Ao H H 0 N ^ ^^j 011 
CB/ 
(a) (b) 
/NHv NOH 
E.0/\/ ^/\0R Ko/\/ V\ UH 
CHOH x x/ x/ x CH. 2 
(c) (d) 
According to formula (c) it is dioxybenzhydrol with the NH linkage : 
calculated 1380 x 0 39 x 078 = A 420. 
According to formula (d) the calculation is 1380 x 0'65 x 0-47 = A 422. 
The difference is due merely to the factors not yet being accurately known 
to three places of decimals. Observed A 421. 
(27) Benzoflavine. — This has the formula : 
Ph 
The calculation involves A 1400 for the two aniline rings, multiplied by 
(a) the CHOH factor, (b) the NH factor, (c) the phenyl factor, (d) the 
square of the orthomethyl factor (see example No. 7). The calculated value 
is 1400 x 0-39 x 078 x 1-026 x (T012) 2 = A 449. The observed value was 
about A 454. 
(28) Dioxyphenazine. — This, being symmetrical, has only two formulae, 
viz. : 
hq/yT Y x ,oh Ho/y NH Y>H 
ill and 
Its calculated A is 1380 x 0 78 x 0 47 = A 506. Observed A 510. 
(29) Neutral red. — This is dimethyldiamino-toluphenazine. The parent 
rings are one aniline and one dimeth vlaniline ring, the value of which 
(see No. 25) is v/1400 x 1548 = A 1473. This is to be multiplied by the 
NH and NOH factors and by 1012 for the ortho-methyl group (see No. 27). 
Calculated A 546. Observed A 540 (commercial specimen). 
(30) Safranine. — This has the formula (when hydrated) : 
NH 2 /X/ NPh \/\nH, 
