In connection with this subject, there is one fact worthy of notice; a plate with a very heavy coating of pure silver, will not produce an equally developed image, as a plate with a thinner coating, hence the thin coating, providing it entirely covers the surface, is the best, and is the one most to be desired.

The experiment is plain and simple.

Let the slate receive a heavy or thick coating by the electrotype, then polish, coat, expose in the usual manner, and the result will be a flat, ashy, indistinct impression; when, on the other hand, the thin coating will produce a bright, clear and distinct image, with all the details delineated.
The style of battery best for the purpose has been, and now is, a question of dispute among operators; some preferring the Daniell battery to Smee's.

Some claim the superiority of the first from its uniformity of action; others, of the latter, for its strength.

I consider either good, and for the inexperienced would prefer the Daniell.