This process avoids stopping-out altogether, and the progress of the work may be judged of with tolerable certainty. The ground is a solution of beeswax in turpentine. Decant the solution till no sediment remains; it should be perfectly fluid, and of a bright yellow colour. Add about one-sixth of its volume of japan varnish; this quantity will vary slightly according to the heat of the weather. If there is too much japan, the ground will be hard and brittle; if there is too little, it will not be strong enough to take smoke with safety. Clean the plate with engravers' emery paper, and place it in a bath of 100 grammes hydrochloric acid, 20 grammes chlorate of potash, 880 grammes water. When the plate darkens all over, it is a sign that there is no grease on it, and it is then ready to receive the ground. Pour on the gronnd as photographers pour collodion, and let it dry for 12 hours; apply a second coat of ground in the same manner, and smoke the plate immediately without waiting for it to dry. The ground should then be even and smooth, and ought to be used a few days after it is laid, as it hardens in time. If in haste to use the plate, the first coat of ground may be dried over a spirit lamp until it becomes transparent; cool the plate, and proceed as before described.

The use of the two coats of ground is to prevent the smoke penetrating to the plate, and causing the ground to become detached in the acid bath. Should the ground be too hard, increase the proportion of the wax solution. Draw all the dark parts first; plunge the plate into a bath of nitric acid for half the time necessary to complete the biting. In temperate weather this would be half an hour; the first biting would, therefore, take about 15 minutes. Remove the plate, dry on blotting-paper, draw the next darkest lines where required, and replace the plate in the bath for a quarter of the total time. This process is repeated, and the plate, with the paler work, is replaced in the bath for one-eighth of the total time. The palest work of all is last drawn, and the plate is plunged into the bath for an eighth of the total time. Thus, the plate will have had the darkest lines in acid the whole time required, the darker lines half the time, the pale lines a quarter, and the palest lines one-eighth of the time, as each biting-in has the advantage of those which preceded it.

Finish with the dry point where required.