METALS.

275

oxygen, that they obtain it both from the air andfrom water, and by condensing it in a solid form,produce the heat which raises the temperatureof the water in such a remarkable degree.

EMILY.

Tiut if pyrites obtain oxygen from water, thatwater must suffer a decomposition, and hydrogentras be evolved ?

O

MRS. B

That is actually the case in the hot springs al-luded to, which give out an extremely fetid gas,composed of hydrogen impregnated with sulphur.

CAROLINE.

If I recollect right, steel and plumbago, whichyou mentioned in the last lesson, are both car-burets of iron ?

MRS. B.

Yes ; and they are the only carburets of muchconsequence.

A curious combination of metals has latelyverv much attracted the attention of the scien-tific world: I mean the stones that fail from theatmosphere. They all consist principally of na-tive or pure iron which is never formed in thatstale in the bowels of the earth; and containalso a small quantity of nickel and chrome, an G