( 523 ) 
2 Cis Hy, NO, + O, a S16 Ho Ns 0, -{- 2 Cs Hs Os 
or rather: 
C,, Hy, NO, + H, O = C, Hi, O; + Cs H, NO 
2 Cs Hy NO + Oa = 2 Ho O + Cig Hio Ng Op 
but the experiment will have to be repeated on a larger scale so 
as to be able to judge of the purity of the indigo-blue and ascertain 
its percentage of indigo-red which also seems to be formed. 
We also wish to state that during this investigation not the least 
difference was noticed between the indican prepared from Indigofera 
leptostachya and that obtained from Polygonum tinctorium and we, 
therefore incline to the belief that both plants contain the same 
indican. As soon as larger quantities of indican are again at our 
disposal, we hope to continue and extend the investigation of this 
important compound. 
The following results were obtained when subjecting indican te 
ultimate analysis. The sample was dried in vacuo over suiphuric acid. 
I. 0.2416 gram of indican (Indigofera) yielded on combustion 
with copperoxide in a current of oxygen 0.4960 gram of carbon 
dioxide and 0.1257 gram of water. 
IL. 0.2397 gram yielded 0.4928 gram of carbon dioxide and 
0.1244 gram of water. 
III. 0.1539 gram of the indican treated by the KJELDAHL- 
GUNNING process yielded 5.12 ce. of N/, ammonia. 
IV. 0.6310 gram similarly treated yielded 20.60 ee. of Nii 
ammonia. 
On comparing the percentages of carbon-hydrogen and nitrogen 
with those calculated from MARCHLEWSKI’s formula: 
Calculated for C'* H'7 NOS, 
i II. UI. IV. 
C 56.0 pCt. 56.1 pCt. — — 56.95 pCt. 
H 5.8 pCt. 5.8 pCt. -- — 5.76 pCt. 
N — — 4,7 pCt. 4.7 pCt. 4.75 pCt. 
it is apparent that while the figures for the hydrogen and nitrogen 
practically agree, those of the carbon are somewhat too low. We, 
therefore, repeated the determination of carbon by means of the 
38* 
