Your copper must be well planisht, that it may lie level; and before you lay on the ground, take your plate, and with a charcoal well burnt coal it over with very clean water; then wash it off with clean water never used before, and set it sloping to run off; when it is dry, then scrape some chalk fine all over it, and with a very clean fine rag rub it over; but let not your fingers touch upon the plate, till you have put the ground on, which you must lay on thus.