i68 Mr. Charles O'Neill on 



sodium salt of a new acid, and other substances. The 

 reaction may be expressed in this way, using H instead of 

 Na for greater clearness. 



C 8 H 5 NO 

 C 8 H 5 NOJ 



+ C s HbNO + C 8 H 7 NO, 



O {qr'o} + 3H0H = 2 ( c * H * o 



or shorter 



C 8 H 5 NO + 2 (HO) = C 8 H 7 N0 3 . 



This acid is precipitated from its soda solution by 

 mineral acids, and the yield is about 25 °/^ of the weight of 

 the aceto body. It is sufficiently soluble in boiling water to 

 obtain it in well-defined crystals. Cold water only retains 

 one part of the acid in one thousand ; it is very soluble in 

 strong or dilute alcohol. At first I thought I had obtained 

 the true isatic acid, which has not yet been isolated, but 

 upon combining it with bases I found it to be a polybasic 

 acid of a high molecular weight. The formula above 

 deduced must be multiplied by four, and comes 

 C32H28N4O12 ; molecular weight 660. The acid crystallises 

 from water and dilute alcohol in fine yellowish coloured 

 needles ; it can be made quite white by treatment with 

 animal charcoal ; it has a distinct acid reaction to litmus. 

 Its melting point is about 190° C, when it begins to decom- 

 pose, giving off, among other things, aniline, which can be 

 readily recognised. It forms at least two salts with soda. 

 The neutral salt C s2 H 26 Na 2 N 4 Oi 2 is very soluble in water, 

 does not crystallise, but dries up to a gummy looking mass; 

 the acid salt C 32 H 27 NaN 4 12 is less soluble in water, and 

 crystallises pretty well from its hot solution. The silver 

 and lead salts are insoluble in water, but the copper and 

 some other metallic salts are soluble and crystallisable. 



Decomposition with strong acetic acid. When the oxy- 

 aceto-body is heated along with mono-hydrated acetic 

 acid, another kind of decomposition takes place, the 

 whole is broken up, indigo blue is seen in suspension, 



