372 
DR. E. DIVERS ON THE UNION OE 
Zinc oxide , cadmium oxide , and cupric oxide dissolve. 
Mercuric oxide dissolves. The solution may be largely diluted with water without 
yielding a precipitate ; and hydrochloric acid may be added to it without causing one 
until the liquid becomes acid, when a white one falls. Nitric and sulphuric acids give 
no precipitates. Sodium hydrate gives a yellowish precipitate, and potassium iodide 
a pale yellow one, turned scarlet-red by acids. 
Cobalt oxide is slightly soluble, and colours the liquid a faint red-pink. The liquid 
gives a slight precipitate with ammonia hydrosulphide, which increases on standing. 
Ferric oxide. A minute quantity of it dissolves and is thrown down by water as 
ferric hydrate. 
Chromium trioxide reacts rather violently, and is converted into a yellow substance 
(ammonia chromamate 1), quite insoluble in the liquid, but freely soluble in water. 
Molybdenum trioxide is converted into a bulky white substance (ammonia molybda- 
mate X), which is insoluble in the liquid, but soluble in water. 
Arsenic trioxide is converted into a coherent mass, insoluble in the liquid, soluble in 
water. 
Phosphorus pentoxide reacts rather energetically at the surface of the mass, in con- 
sequence no doubt of absorbed water (see phosphoric chloride). The rest of the oxide 
is very slowly acted upon, and undergoes no change in appearance. Much of it 
dissolves, probably as phosphamate (phosphates are almost or quite insoluble). The 
changed oxide dissolves quietly in water, and gives the reaction of a phosphate. 
For on oxide is very slightly soluble. The undissolved portions are unchanged in 
appearance, but the (vitreous) fragments of it become opalescent in water. 
Carbon dioxide forms a solid substance, some of which dissolves in the liquid, and 
which is no doubt ammonia carbamate. 
Silica , alumina , tungsten trioxide, chromium sesguioxide, tin dioxide, manganese 
dioxide , and lead dioxide are unaffected. 
Carbon bisulphide is insoluble, but gradually combines with the ammonia. 
Potassium hydrate causes an effervescence of ammonia, and rapidly dissolves. Its 
dissolution is followed by the deposition of most of the potassium as an insoluble com- 
pound, which is probably the nitrate. 
Sodium hydrate is only slowly acted upon. A little of it dissolves, a crystalline 
matter (sodium nitrate) is deposited, and the liquid becomes richer in ammonia. 
Potassium salts are only very slightly soluble, and in some cases evidently undergo 
decomposition with the ammonia nitrate. 
Sodium salts dissolve to a small extent, or undergo decomposition, so as to yield a 
sodium compound in solution (sodium nitrate). 
Ammonia salts are soluble or insoluble according to their nature. The behaviour of 
other salts, so far as the basylous radical is concerned, can be judged of by that of the 
chlorides. 
Potassium chlorate is slightly soluble. 
