Nitrate of silver 1 oz.
Distilled water 10 oz.
Dissolve.
Iodide of potassium 5 grs.
Distilled water 1 dr.
Dissolve.
On mixing these two solutions, a precipitate of iodide of silver is formed. Place the bottle containing this mixture in a saucepan of hot water, keep it on the hob for about twelve hours, shake it occasionally, now and then removing the stopper. The bath is now perfectly saturated with iodide of silver; when cold, filter through white filtering paper, and add—
Alcohol 2 drs.
Sulphuric ether 1 dr.
The prepared glass is to remain in the bath about eight or ten minutes. Now, is this bath applicable to all collodion, or only to that prepared by Mr. Thomas; and if the former, what is the rationale of its beneficial action?