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,[943] and in sheets, alum; for lead and marble, resin. Lead is also united by the aid of white lead;[944] white lead with white lead, by the agency of oil; stannum, with copper file-dust; and silver, with stannum.[945] 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.[946] Limestone and Thracian stone[947] 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,[948] 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. CHAP. 31. (6.)—SILVER. After stating these facts, we come to speak of silver ore, the next[949] folly of mankind. Silver is never found but in shafts sunk deep in the ground, there being no indications to raise hopes of its existence, no shining sparkles, as in the case of gold. The earth in which it is found is sometimes red, sometimes of an ashy hue. It is impossible, too, to melt[950] it, except in combination with lead[951] or with galena,[952] this last being the name given to the vein of lead that is mostly found running near the veins of the silver ore. When submitted, too, to the action of fire, part of the ore precipitates itself in the form of lead,[953] while the silver is left floating on the surface,[954] like oil on water. Silver is found in nearly all our provinces, but the finest of all is that of Spain; where it is found, like gold, in uncultivated soils, and in the mountains even. Wherever, too, one vein of silver has been met with, another is sure to be found not far off: a thing that has been remarked, in fact, in the case of nearly all the metals, which would appear from this circumstance to have derived their Greek name of “metalla.”[955] It is a remarkable fact, that the shafts opened by Hannibal[956] in the Spanish provinces are still worked, their names being derived from the persons who were the first to discover them. One of these mines, which at the present day is still called Bæbelo, furnished Hannibal with three hundred pounds’ weight of silver per day. The mountain is already excavated for a distance of fifteen hundred[957] paces; and throughout the whole of this distance there are water-bearers[958] standing night and day, baling out the water in turns, regulated by the light of torches, and so forming quite a river.