A Jones reductor is a device used to reduce aqueous solutions of metal ions.
After washing to remove salts, the amalgam is placed in a long glass tube, similar to a chromatography column, equipped with a stopcock.
The length of the column or the flow rate are adjusted to effect full reduction of the soluble reagent.
These operations might include iodometric titration to determine the reducible content of the effluent.
In some cases, the effluent is treated with other reagents to precipitate a compound of the reduced ions.