PRODUCTS DERIVED FROM INDIGO-BLUE. 83 



Anthranilic Acid, 



Though there could be no doubt^ after an examination of 

 the properties of the crystallized acid formed in this process, 

 of its identity with anthranilic acid, still I conceived that 

 its analysis, if not altogether indispensable, might prove of 

 some interest. The results obtained were as follows : — 



I- 0"3i35 grm., dried at ioo° C, gave 07035 grm. car- 

 bonic acid and 0*1500 grm. water. 



0*4050 grm., burnt with soda-lime, gave 0*2890 grm. 

 metallic platinum. 



II. 0*1664 grm. gave 0*3720 grm. carbonic acid and 

 0*0780 grm. water. 



0*5590 grm. gave 49 cc. of moist nitrogen at 7° G. and 

 759*2 millims. pressure, equivalent to 47*25 cc. dry nitrogen 

 at 0° C. and 760 millims. pressure, or 0*0591 grm. 



These numbers correspond with the formula C,4.H^ NO4, 

 which is that of anthranilic acid, as the following compa- 

 rison of the composition with that required by theory will 



show : — 



r< 1 1 .• Experiment. 



LalcLilation. -r ^ j-r 



Cj^ 84 61*31 6i'i9 6o'97 



H7 7 5-10 5-31 5-20 



N 14 io'2i 10T3 10-58 



0^ 32 23-38 23-37 23-25 



137 • loo-oo 100-00 lOO'OO 



Since under ordinary circumstances this acid can only be 

 obtained by the long-continued action of boiling concen- 

 trated alkaline lye on indigo-blue, its formation in this 

 process, in which only a small quantity of caustic soda dis- 

 solved in a large quantity of alcohol was employed, is re- 

 markable. There can be little doubt that its formation in 

 this case is connected in some way with that of the other 

 substances, and could not be effected by the mere action of 

 a dilute alcoholic solution of caustic alkali on indigo-blue. 



The experiments just described suggest a few general 



g2 



