such things may make glass out of a straw, by burning it and heating the
ashes with a blowpipe. A little globule of pure glass will form as the
ashes are consumed. The following curious instance, quoted by that
interesting physiologist, Dr. Carpenter, shows the same effect upon a
large scale. A melted mass of glassy substance was found on a meadow
between Mannheim and Heidelberg, in Germany, after a thunder-storm. It
was, at first, supposed to be a meteor; but, when chemically examined,
it proved to consist of silex, combined with potash,--in the form
in which it exists in grasses; and, upon further inquiry, it was
ascertained that a stack of hay had stood upon the spot, of which
nothing remained but the ashes, the whole having been ignited by the
lightning.

There is nothing in Nature more striking to the novice than the first
suggestions of the various, and apparently contradictory, at least
unexpected, positions in which the same mineral is found. Now carbon is
one of the minerals whose exchanges are peculiarly interesting. Chemists
say that the diamond is the only instance in Nature of pure carbon:
it burns in oxygen under the influence of intense heat, and leaves no
ashes. Next to this--strange gradation!--is charcoal, which comes within
a very little of being a diamond. But just that little interval is
apparently so great, that none but a chemist would suspect there was
any relationship between them. Then come all those immense beds of coal
which compose one of the geological strata of the earth's crust, a
stratum that was formed before the appearance of the animated creation,
when the earth was clothed with a gigantic forest, whose mighty trunks
buried themselves with their fallen leaves, and became, in time, a
continuous bed of carbonaceous stone.

If we look at the vegetable and animal kingdoms, we find carbon entering