While speaking on this subject, it will be as well to annex the remaining particulars, that our admiration may here be drawn to all the marvels presented by Nature in connection therewith. The proper solder for gold is that above described; for iron, potter's clay; for copper, when in masses, cadmia,[1] and in sheets, alum; for lead and marble, resin. Lead is also united by the aid of white lead;[2] white lead with white lead, by the agency of oil; stannum, with copper file-dust; and silver, with stannum.[3]

For smelting copper and iron, pine-wood is the best, Egyptian papyrus being also very good for the purpose. Gold is melted most easily with a fire made of chaff.[4] Limestone and Thracian stone[5] are ignited by the agency of water, this last being extinguished by the application of oil. Fire, however, is extinguished most readily by the application of vinegar, viscus,[6] and unboiled eggs. Earth will under no circumstance ignite. When charcoal has been once quenched, and then again ignited, it gives out a greater heat than before.