116 Transactions of the Royal Society of South Africa. 
Table III. 
No. 
Name. 
Colour in Alkali. 
Wave-length 
of Absorption 
Band. 
1 
Plienol-3'-iiitroplitbalein . 
Pink 
559 
Easily bleached by 
excess alkali. 
2 
Tliymol-3'-mtroplitlialein . 
Blue 
602 
Easily bleached by 
excess alkali. 
3 
E,esorcinol-3'-nitrophtha- 
Salmon (green 
495 
( = 3'-nitrofluores- 
lein 
fluorescence) 
cein). 
4 
a-naplitliol-3'-nitroplitha- 
Brown (blue 
About 730 
lein 
fluorescence) 
The 3'-iiitro-group has thus quite a small effect, quite different from 
that of iiitro-groups in the phenol rings. 
In addition, resorcinol-3'-oxyplithalein (3'-oxjfiuorescein) has been made 
from 3-oxyphtlialic acid. Its absorption-band wave-length is A 489. 
Resorcin-saccharein, which is fluorescein with SO^NH instead of CO'O, 
is identical in appearance and spectrum with fluorescein. 
