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COLOUE AND CHEMICAL CONSTITUTION. 
Part XV. — A Systematic Study of Fluorescein and 
Kesorcin-benzeine. 
By James Moir. 
In Part XI of this work (These T., Vol. IX, part 2, p. 129) a systematic 
study of phenolphthalein was undertaken, as a result of which the colour- 
value of substitution (by bromine taken as a standard substituent) of every 
one of the twelve hydrogen atoms in this compound was approximately 
determined. 
As the nature of this investigation does not seem to have been 
fully understood overseas, e.g. by the abstractor of the London Chemical 
Society, I think it desirable to reprint the results in another form, viz. 
that of the " dicyclic colour-factors " explained in Parts X and XIV. 
Table of Colour -factors for Bromine in Phenolphthalein. 
Colour-factor. 
Bromine substituted for hydrogen in the a position = 1-0180 
b 
„ =1-0020 
c 
„ =1-0145 
d 
„ =1-0180 
55 55 55 ') € 
„ =1-0270 
f 
„ =1-0145 
9 
„ =1-0145 
h 
„ =1-0270 
55 55 55 55 * 
„ =1-0235 
j 
„ =1-0125 
k 
„ =10125 
I 
„ =1-0235 
Note. — The numeration of the positions is that given on p. 130 of Part 
XI, and is also repeated here under fluorescein. 
Thus to calculate the colour of phenol-tetrabromophthalein (which is 
