Preparing the Printing-ink for Use.—116. With a suitable knife, remove from the can a piece of ink of the size of a nut, and place it upon the slab. From the varnish-can take as much thin varnish as will lie upon the end of the palette-knife, and transfer it to the upper part of the slab. A small quantity of this varnish must now be mixed with the piece of ink by means of the palette-knife. At first there will be a difficulty—the ink being very tenacious will not easily separate, to allow of mixture with the varnish; but by industriously working it with the knife it will gradually yield and be incorporated with it. When this has once taken place, more varnish may easily be added if required. It is to be supposed that our students’ first essay at printing will be a simple subject in line-work, a bill-head, circular, or such like. The temperature of the room in which the printing is to be carried on being moderate, the mixture of ink and thin varnish is to be such that it will run slowly off the palette-knife when held in a position to allow it to do so. It is better to err in having the varnish too thick than too thin. When the ink has been brought to a proper consistency, it is to be scraped off the slab and laid upon that portion of it farthest from the printer.