There is a mode of transferring draw ings made with the chemical ink on pa per prepared with a solution of size or gain tragacanth, which being laid on the stone and passed through. the press leaves the drawing on the stone, and the pro cess above described for preparing the atone and taking the impression is carried into effect.
In Germany many engravings are made on stone with the burin, in the same way as on copper ; but the very great inferi ority of these to copper engravings makes it improbale that this method will ever come into general use.
Perhaps one of the greatest advantages of the art of lithography is the extraordi nary number of copies that may be taken from a block. As many as 70,000 copies Or prints have been taken from one block, and the last of them nearly as good as the first. Expedition is also gained, inas much as a fifth more copies can be taken in the same time than from a copper plate: and as regards economy the ad vantages over every other species of en graving is very great.
Zincography. This art, which is of very recent introduction in this country (so much so, indeed, that but few specimens are as yet to be seen), is similar in princi ple to lithography, the surface of the plates of zinc on which it is executed being bit away, leaving the design promi nent or in relief. We have seen some
beautiful examples of this art, but vary ing little in their appearance from those of stone engraving.
Mr. J. II. Priny, of England, has pro posed a mode of engraving on steel and other metals by means of electricity. He employs six of Smee's batteries, in each the size of the platinized silver plate was about three square inches. The steel plate to be engraved was connected to the zinc end of the batteries ; a long covered wire is placed between the steel plate and the zinc. The wire in communication with the platinized silver, was used as an etch ing point on the steel plate. The wire, which served as a graver, was made of platina ; when held a glass tube protected it from the hand. In proportion to the intensity of the current is the depth of the engraving.