Products of the Distillation ofMeconic Acid. 135 



II. 0-3510 gramme gave 0-444 of carbonic acid and 0-0920 

 of water. 



Calculated numbers. Percent. 

 Carbon =1834-440= 34-94 

 Hydrogen = 137*274= 2-61 

 Oxygen =2300'000= 43*80 

 Fe 2 O 3 = 978-424 = 18-63 

 5250-138 100- 00 



These analyses give the formula KO + 2 HO+KO+HO 

 + Fe 2 3 + 4 aq = C 12 H 4 O 10 +2 HO C ]2 H 4 O ]0 + HO + Fe 2 

 O a + 4aq. 



The salt employed for these determinations was made at 

 three different times. 



Komenate of ammonia, when treated with persulphate of 

 iron, also yields this salt, just as when the acid alone is em- 

 ployed. I determined the quantity of iron contained in a 

 portion of salt made in this way and dried at 212° F. 0*2782 

 gramme gave 0*052 of peroxide = 18*69 per cent. 



If persulphate of iron is added to a hot instead of a cold 

 solution of kornenic acid, which is kept for some hours at a 

 temperature of about 150° F., none of these jet-black crystals 

 are deposited. The red colour also of the liquid disappears, 

 and it becomes transparent, and has a deep yellow colour. 



A solution of galls produces in it no change of colour, but 

 it gives a deep blue with red prussiate of potash, and a white 

 precipitate changing to blue with the yellow prussiate. These 

 reactions clearly show that the peroxide of iron has been re- 

 duced by the kornenic acid to the state of protoxide. The red 

 colour of the liquid was not restored by the addition of more 

 kornenic acid, but it immediately returned when more per- 

 sulphate of iron, or a little nitric acid was added. A consi- 

 derable quantity of persulphate was poured into the liquid, 

 which was then set aside in a hot stove for twelve hours, when 

 its red colour had again disappeared, and a small quantity of 

 bright yellow crystals were found at the bottom of the liquid. 

 These crystals were but of small size, but larger than those of 

 the komenate of iron; they possessed considerable lustre, 

 and were but slightly soluble in cold water. When heated 

 they inflamed and left a considerable quantity of black oxide 

 of iron, which showed that they consisted of an organic pro- 

 tosalt of iron. 



If the crystals are digested with solution of potash the iron is 

 precipitated in the state of protoxide ; and when the clear alka- 

 line liquor is separated and is neutralized with muriatic acid, 

 it does not strike a red colour with persulphate of iron, which 

 clearly shows that the acid in these crystals is not the kornenic. 



