374 
DR. E. DIVERS ON THE UNION OF 
mixed with water, may be boiled alone or with hydrochloric acid, without undergoing 
any change. Boiled with caustic soda, it loses its colour, and deposits a little chromic 
hydrate (see the chloride). 
Potassium sulphite and sodium hydrogen sulphite are very slightly decomposed, and a 
trace only of sulphite passes into solution. 
Ammonia chromate , yellow, crystalline, is converted into a much more voluminous, 
amorphous, yellow substance, quite insoluble in the liquid, but soluble in water. If 
not thoroughly dry, the chromate imparts a yellow colour to the liquid, but not other- 
wise ; and even this disappears after a time by the deposition of all the chromium salt. 
Ammonia anhydro or red chromate is very slowly converted into a yellow deposit, 
which is not voluminous as in the preceding case. The liquid is not coloured by the salt. 
Potassium chromates, yellow and red , are slowly acted upon superficially, with the 
production of a yellow amorphous substance. The yellow chromate faintly colours the 
liquid, and both yield potassium salt to it. Although in the case of the anhydro 
chromates and of chromium trioxide ( vide supra) ammonia chromate is probably 
formed, it is also evident the ammonia forms ammoniated ammonia chromate. A 
similar union appears to take place between ammonia sulphate and ammonia. 
Lead chromate is converted into a bulky yellow deposit, which by water is recon- 
verted into lead chromate. It hardly colours the liquid, but some lead dissolves. 
Potassium permanganate readily dissolves, imparting its splendid colour to the liquid. 
A very gradual formation of gas soon commences and continues for a day or two, the 
liquid changing at the same time in colour and becoming deep yellow-brown. The 
liquid when of this colour is still transparent, but gradually yields a brown deposit 
and becomes of a fine dilute indigo tint. This shade of colour, lastly, slowly passes into 
a bright purple colour, which appears to be permanent. In this state the liquid is 
found not to contain much manganese ; its bright colour is spoiled by water and dis- 
charged by acids. The brown deposit, on treatment with water, swells up into a bulky 
flocculent matter, presumably manganic hydrate. Potassium permanganate dissolved 
in ammonia-water is entirely decomposed in some hours; but in the presence of 
ammonia nitrate, which by itself is inactive, the permanganate is much more rapidly 
decomposed by the ammonia-water — probably because of the production, at first, of 
ammonia permanganate by the nitrate. 
Potassium carbonate gradually disappears, some potassium nitrate taking its place. 
In consequence of the destruction of some of the ammonia nitrate, the liquid becomes 
surcharged with the ammonia, which has lost its solvent, and effervesces copiously. 
The liquid contains some potassium salt and some carbonate. 
Sodium carbonate behaves like the potassium salt, but to a very limited extent. A 
similarly marked difference in intensity has been already indicated as marking the 
action of potassium and sodium hydrates. 
Calcium carbonate is not acted upon. 
Ammonia carbamate is moderately soluble. 
