PRODUCTS OF DECOMPOSITION OF COMENIC ACID. 
of the acid in a slight excess of ammonia, and subsequent concentration in vacuo 
over sulphuric acid. He describes it as “ partly amorphous, partly crystalline :” 
he found that it lost two equivalents of water on drying at 212°. As obtained by 
the process above given, it is in the form of square prismatic crystals, white and 
of great brilliancy, presenting when in mass a beautiful appearance. It is very 
soluble in boiling water, very little soluble in alcohol. It has a strong acid re- 
action, and is deposited even from a solution of the acid in an excess of hot caustic 
ammonia, if the boiling has not been continued. It is represented by the formula 
NH,0, HO, C,, H,O, + 2 aq. 
in ammonia. It falls in groups of radiated prisms. 
5°193 grains of the air-dried salt lost at 212° Fahr. 
0-713 a water. 
sponding to the formula 
NH,0, HO, C,, H,O, + 3 aq. 
Bicomenate of Potass. 
potass was determined by ignition with a few drops of strong sulphuric acid. 



6-250 grains air-dry salt gave 
8-497 ... carbonic acid, and 
0987 ... water. 
5:291 grains gave 
2335 ... sulphate of potass. 
Experiment. Calculation, 
-eeCQ Se eee 
Carbon, : 37-07 37:07 C,. 72 
Hydrogen, . 175 1:54 H, 3 
Oxygen, : Be 37:09 0, 72 
4 Potass, 5 23:88 24-30 Ko 47:2 
100-00 100-00 194-2 
The formula of the above salt is therefore 
KO, HO, C,, H, 0,. 

My own analyses agree with this, which is the result of the analyses of Dr 
STENHOUSE; but a salt containing an additional single atom of water is obtained 
when strong alcohol is added to cold saturated alkaline solution of comenic acid 
The per-centage calculated from the number is 13°73, while 13:50 is that corre- 
Bicomenate of ammonia, in the dry state, sustains a temperature of 350° Fahr. 
without decomposition or loss of weight. When heated to 390° Fahr. in a closed 
tube, it blackens and fuses, and on examination it is found to have undergone a 
change, an acid substance being produced, which I shall describe fully hereafter. 
When comenic acid is boiled with a slight excess of caustic potass, it dissolves 
readily, and the fiuid on cooling deposits a salt, which, when washed with cold 
water, and subsequently recrystallized from the same menstruum boiling, presents 
itself in groups of short, square, prismatic needles. They are not very readily 
deprived entirely of colour. They have a strongly acid reaction, and are the an- 
hydrous bicomenate of potass. They gave the following results on analysis; the 
