SULPHUR.

101

made of glass, like this, which is applicable onlyto distillations upon a very small scale. Thoseused in manufactures arc generally made of cop-per, and are, of course, considerably larger. Theprincipal construction, however, is always thesame, although their shape admits of some varia-tion.

CAROLINE.

What is the use of that neck, or tube, whichbends down from the upper piece of the appa-ratus ?

MRS. B.

It is of no use in sublimations; but in distilla-tions (the general object of which is to evaporate,by heat, in closed vessels, the volatile parts of acompound body, and to condense them again intoa liquid), it serves to cany off the condensed fluid,which otherwise would fall back into the cucur-bit. But this is rather foreign to our present sub-ject. Let us return to the sulphur, \ounovvperfectly understand, I suppose, what is meant bysublimation ?

EMILY.

I believe I do. Sublimation appears to consistin destroying, by means of heal, the attractionof! aggregation of the particles of a solid body,which are thus volatilized ; and and as soon as