You said that rust was an oxyd of iron; how is it, then, that water, or merely dampness, produces it, which, you know, it very frequently does on steel grates, or any iron instruments?
MRS. B.
In that case the metal decomposes the water, or dampness (which is nothing but water in a state of vapour), and obtains the oxygen from it.
CAROLINE.
I thought that it was necessary to bring metals to a very high temperature to enable them to decompose water.
MRS. B.
It is so, if it is required that the process should be performed rapidly, and if any considerable quantity is to be decomposed. Rust, you knew, is sometimes months in forming, and then it is only the surface of the metal that is oxydated.
EMILY.
Metals, then, that do not rust, are incapable of spontaneous oxydation, either by air or water?
MRS. B.