Colour and Chemical Constitution. 
237 
III. a-Naphthofluorane in cone. H 2 S0 4 has AA 500 and 475. 
IV. Phenosafranine (" desensitol ") has AA 525+505 in water, and 
AA 532+497 in alkali. 
V. Quinhydrone in AmHC0 3 : A 480 broad. 
VI. Tetrabromo-quinhydrone in NaOH : A 510. (2-2 , -6-6 / variety.) 
VII. Quinhydrone of dimethylphenylenediamine : AA 558+513. 
VIII. „ tetramethylphenylenediaraine ; AA 614+568. 
IX. „ „ dihydrophenazine : AA 701+640. 
Note. — The quinhydrones obey the dicyclic colour laws, but the 
oxidation-factor is f, not ■§. 
