The strength of the solution may be kept up by occasionally adding the chloride of silver and cyanide of potassium.

There should alway be a very little excess of the cyanide.
The plate should be well cleaned and buffed, and the solution well stirred before it is immersed.

Care should be observed to keep the solution clean, and allow no particle of dust to come in contact with the surface of the plate.

The plate is now to be attached to the pole of the battery.
After remaining a short time, it assumes a blue color; take it out, rinse freely with pure water, then dry with a spirit lamp, and it is ready for buffing.

Buff and coat in the usual manner.