sume in all my readers some slight knowledge about lime.
I shall take for granted, for instance, that all are better informed
than a certain party of Australian black fellows were a few years
since.

In prowling on the track of a party of English settlers, to see what
they could pick up, they came--oh joy!--on a sack of flour, dropped
and left behind in the bush at a certain creek. The poor savages had
not had such a prospect of a good meal for many a day. With endless
jabbering and dancing, the whole tribe gathered round the precious
flour-bag with all the pannikins, gourds, and other hollow articles
it could muster, each of course with a due quantity of water from the
creek therein, and the chief began dealing out the flour by handfuls,
beginning of course with the boldest warriors. But, horror of
horrors, each man's porridge swelled before his eyes, grew hot,
smoked, boiled over. They turned and fled, man, woman, and child,
from before that supernatural prodigy; and the settlers coming back
to look for the dropped sack, saw a sight which told the whole tale.
For the poor creatures, in their terror, had thrown away their pans
and calabashes, each filled with that which it was likely to contain,
seeing that the sack itself had contained, not flour, but quick-lime.
In memory of which comi-tragedy, that creek is called to this day,
"Flour-bag Creek."

Now I take for granted that you are all more learned than these black
fellows, and know quick-lime from flour. But still you are not bound
to know what quick-lime is. Let me explain it to you.

Lime, properly speaking, is a metal, which goes among chemists by the
name of calcium. But it is formed, as you all know, in the earth,
not as a metal, but as a stone, as chalk or limestone, which is a
carbonate of lime; that is, calcium combined with oxygen and
carbonic-acid gases.

In that state it will make, if it is crystalline and hard, excellent
building stone. The finest white marble, like that of Carrara in
Italy, of which the most delicate statues are carved, is carbonate of
lime altered and hardened by volcanic heat. But to make mortar of
it, it must be softened and then brought into a state in which it can
be hardened again; and ages since, some man or other, who deserves to
rank as one of the great inventors, one of the great benefactors of
his race, discovered the art of making lime soft and hard again; in
fact of making