“By the weight, chiefly. Gold is much heavier than brass; it is indeed the heaviest metal in frequent use. After it comes lead, then silver, copper, iron, tin, and finally zinc, the lightest of all.”
“You told us that to melt copper,” put in Emile, “they needed a fire so intense, that the heat of a red-hot stove would be nothing in comparison. All metals do not resist like that, for I remember very well in what a sorry way the first leaden soldiers you gave me came to their end. Last winter, I had lined them up on the luke-warm stove. Just when I was not watching, the troop tottered, sank down, and ran in little streams of melted lead. I had only time to save half a dozen grenadiers, and their feet were missing.”
“And when Mother Ambroisine thoughtlessly put the lamp on the stove,” added Jules, “oh! it was soon done for: a finger’s breadth of tin had disappeared.”
“Tin and lead melt very easily,” explained Uncle Paul. “The heat of our hearth is enough to make them run. Zinc also melts without much trouble; but silver, then copper, then gold, and finally iron, need fires of an intensity unknown in our houses. Iron, above all, has excessive resistance, very valuable to us.
“Shovels, tongs, grates, stoves, are iron. These various objects, always in contact with the fire, do not melt, however; do not even soften. To soften iron, so as to shape it easily on the anvil by blows from the hammer, the smith needs all the heat of his forge. In vain would he blow and put on coal; he would never succeed in melting it. Iron, however, can be melted, but you must use the most intense heat that human skill can produce.”
CHAPTER XIII
METAL PLATING
IN the morning some wandering coppersmiths were passing. Mother Ambroisine had sold them the old kettle. Besides the sale, they were to make over the lamp whose foot had melted on the stove, and replate two saucepans. So the smiths lighted a fire in the open air, set up their bellows on the ground, and in a large round iron spoon melted the old lamp, adding a little tin to replace what had been lost. The melted metal was run into a mold, from which it came out in the shape of a lamp. This lamp, still pretty large, was fixed on a lathe which a little boy set in motion; and while it turned, the master touched it with the edge of a steel tool. The tin thus planed off fell in thin shavings, rolled up like curl-papers. The lamp was visibly becoming perfect; it took the proper polish and shape.
Afterward they busied themselves plating the copper saucepans. They cleaned them thoroughly inside with sand, put them on the fire, and, when they were very hot, went over the whole of their surface with a tow pad and a little melted tin. Wherever the pad rubbed, the tin stuck to the copper. In a few moments the inside of the saucepan, red before, was now shiny white.
Emile and Jules, while eating their little lunch of apples and bread, looked on at this curious work without saying a word. They promised themselves to ask their uncle the reason for whitening the inside of the copper saucepans with tin. In the evening, accordingly, they spoke of the tinning and plating.