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.

“Highly cleaned and polished iron is very brilliant,” explained their uncle. “The blade of a new knife, Claire’s scissors, carefully kept in their case, are examples. But, if exposed to damp air, iron tarnishes quickly and covers itself with an earthy and red crust called—”

“Rust,” interposed Claire.

“Yes, it is called rust.”

“The big nails that hold the iron wires where the bell-flowers climb up the garden wall are covered with that red crust,” remarked Jules; and Emile added:

“The old knife I found in the ground is covered with it too.”

“Those large nails and the old knife are encrusted with rust because they have remained for a long time exposed to the air and dampness. Damp air corrodes iron; it becomes incorporated with the metal and makes it unrecognizable. When rusty, iron no longer has the properties that make it so useful to us; it is a kind of red or yellow earth, in which, without looking attentively, it would be impossible to suspect a metal.”

“I can well believe it,” said Jules. “For my part, I should never have taken rust for iron with which air and moisture had become incorporated.”

“Many other metals rust like iron; that is to say, they are converted into earthy matter by contact............