You see here I can pour off the supernatant liquid clear, leaving our silver and gelatine as a clot at the bottom of the vessel.
The supernatant liquor is the mordant; it has a density of 11° or 111⁄2° Baumé.
Let it stand to subside; pour off the supernatant liquor; fill up with cold water and let it stand, to again subside.
A little of the supernatant ether is now removed to a small glass capsule or watch-glass, and allowed to evaporate spontaneously.
He then decants the supernatant liquor, and adds to it a fresh quantity of the sulphate along with some iron filings.
It should then be separated by means of a glass funnel from the supernatant liquid, and again washed; this time with simple water.
At the end of this time, the supernatant clear liquid is to be drawn off into congealing boxes, as will be presently explained.
On allowing them to stand, perfect subsidence took place, leaving the supernatant water colorless and brilliant.
Alum forms in it a precipitate of a brown red; and the supernatant liquid retains a yellowish-red colour.
The supernatant liquid will exhibit a fine blue colour, if the minutest quantity of copper be present.