284 
important branch of the German Administration towards it is 
sufficient testimony of the stage at which it then stood. 
1902 some samples of Artificial Indigo were exhibited at the 
Royal Society by the Badische Anilin und Soda Fabrik, of Ludwigs- 
hafen on the Rhine, and the manufacture was described as 
ollows :— 
* The initial material is napthalene ; this is converted by oxida- 
tion with sulphuric acid into phtalic-anhydride, and the latter is 
next transformed into anthranilic acid, which, in conjunction with 
chloracetic acid, yields phenylglycin-orthocarboxylic acid. The 
latter body is treated with a caustic alkali at a high temperature, 
and yields indoxyl or indoxylic acid. 
* It is interesting to note that this product indoxy] also results in 
the treatment of the indigo plant as practised in the tropics. 
“The last stage in the process, whether starting from napthalene 
or from the indigo plant, is identical, viz., the oxidation of indoxyl 
er indigo ” (Deser. Cat. Roy. Soc. Conversaz. May 14th, 1902, 
oF. possibly a better result is obtained by treatment with sulphuric 
2) 
Th hi * “ : 6 p- 2 ° 
1e chemistry of Indigo, mainly devoted to analysis of the com- 
. 7 atu yuthetic Indigo carried out at 
bags o ~ indicate that the natural ays goes further 
Chemisty a. i 3). ye (Burkill & Anneti, Industr. and Agric. 
Cloth dyed entirely with § i : : 
7 ynthetic Indigo fades in about two 
months, but a mixture of the artificial and ctor! product is more 
durable and also ee 5 colour than the Natural Indigo (Journ. 
Pp: ; 
in sh ld j ialit 
of the plant falls off (Burkill anal Range oe eg re 
