Some operators are in the practice of immersing the plate in the solution and buffing twice.

This additional silvering is no improvement wherever there has been a proper first coating.
Sometimes the operator is troubled with streaks or scum on the plate.
This may arise from three causes, all of which experience must teach the experimenter to avoid; first, too great an excess of cyanide in the solution; second, a lack of silver; third, the current too strong.
Another annoyance arises from the solution being dirty and the dirt collecting on the surface.

When this is the case, the dirt is sure to come in contact with the surface of the plate as it is plunged into the solution, and the result is a scum that it is difficult to dispose of.
This can be prevented only by frequent filtering.

One thing should always be borne in mind in electrotyping Daguerreotype plates--that in order to secure a perfectly coated surface, the plate should be perfectly cleaned.

In this point, many who have tried the electrotype process have failed, attributing their ill success to other than the proper cause.
DAGUERREOTYPES WITHOUT MERCURY.
The following process possesses some interest, and is worthy a trial from operators.