THE COHEX AND THE BEITISH PHABMACOPOilA. 
725 
of iron, oxide of zinc by the dry and moist process, calcined magnesia or mag- 
nesic oxide, hydrate of magnesia, quicklime, lime-water, caustic potash, pure 
potash, pnudre de Vienne or caustic potash with lime, solution of caustic soda, 
and liquid ammonia are contained in this chapter. 
It is not necessary to extend very much the remarks upon some of these 
oxides ; the crystallized oxide of antimony prepared by burning metallic anti¬ 
mony at the bottom of a large red-hot crucible is not met with in Englisli 
pharmacy ; the precipitated oxide of antimony corresponds with the oxide of 
the P. B., carbonate of potash being used instead of soda; the washed diapho¬ 
retic antimony does not represent our tartarized or tartarated antimony. The 
diaphoretic antimony should be perfectly w’hite. It consists (says the Codex) 
in 100 parts, of antimonic acid 7G'99, potash lO’TO, and water 12-31. 
OxYDE HE Meecuee. ITgO = 108. 
33. Oxyde Eouge de Meecuee^. 
Deutoxyde de Mercure, Bloxyde de Mercure, PrecipUe Poiige. Oxyduin 
llydrargyricum. Mercuric Oxide^ Red Oxide of Mercury. 
Pure Mercury.One thousand grammes . . . 1000. 
Nitric Acid, 1-12.Seven hundred and fifty grammes, 750. 
Distilled water.Two hundred and fifty .... 250. 
Introduce the mercury into a flat-bottomed matrass, pour upon it the acid 
and water previously mixed, and place the matrass upon a -warm sand-bath, so 
that the metal may be entirely dissolved ; gradually raise the heat so as to eva¬ 
porate the liquid ; when the nitrate of mercury has become dry, raise the tem¬ 
perature so as to decompose it; maintain the heat sufficiently long that the 
decomposition may be perfect, and that nitrous vapours are no longer set free. 
Let it cool slowly, take out the oxide, which is of a beautiful orange-red, and 
keep in a closed vessel protected from the light. When the temperature is 
raised too much or the heat is too prolonged, the oxide is converted into ox 3 ^gen 
and mercury ; when, on the contrary, sufficient heat has not been used so as to 
decompose all the nitric acid, an oxide is obtained mixed with subnitrate of 
mercury, this second inconvenience should be more carefully guarded against 
than the first. 
When oxide of mercury is prepared in the wet way by precipitating a salt of 
the binoxide of mercury by potash, an oxide is obtained of a yellow colour, 
having the same composition as the former but differing in many other respects. 
Thus, it is most readily attacked by chlorine, it combines with oxalic acid in the 
cold, whilst the red oxide is not affected by this acid ; also it unites readily with 
ammonia, whilst the red oxide combines with extreme slov/ness. Unless ordered 
to the contrary, the red oxide should always be supjDlied. 
In the P. B. process for the red oxide of mercury, only half the mercurj’- is 
dissolved at first in the acid and water, which is to be heated until a dry salt is 
obtained ; with this the remaining mercury is to be well mixed by trituration, 
and then heated in a porcelain capsule with repeated stirring until acid vapours 
cease to be evolved. There is a triteness about the P. B. directions not pos¬ 
sessed by the Codex. 
35. Safean de Maes Apeeitif*. 
Oxyde de Fee IIydeate. 
Oxydam Fcrricum Aqua medianie paraium. Hydrated Oxide of Iron. 
Ferric Oxide prepared by aid of loater. 
This is prepared by mixing solutions of sulphate of iron and carbonate of 
Boda, washing and drying the precipitate known as carbonate of iron, and ses- 
quioxide of the P. Bond. 
