with heavy charges at a target,
the lead is just melted by the heat of impact, and it "splashes," to use
a common phrase. It is obvious from these two examples, that no velocity
which the hand of man is able to give to a steel, when striking a flint,
or to one stick rubbing against another stick, will be competent to
afford a red-hot temperature unless the surface against which impact or
friction is made be very small, or unless great care be taken to avoid
the wasteful dissipation of heat. The spark made by a flint and steel,
consists of a thin shaving of steel, scraped off by the flint and heated
by the arrested motion. When well struck, the spark is white-hot and at
that temperature it burns with bright scintillations in the air, just as
iron that is merely red-hot burns in pure oxygen. This is the theory: now
for the practice.

Flints.--If we may rely on a well-known passage in Virgil, concerning
AEneas and his comrades, fire was sometimes made in ancient days by
striking together two flints, but I confess myself wholly unable to light
tinder with flints alone, and I am equally at a loss to understand what
were the "dry leaves" that they are said in the same passage to have used
for tinder. Neither can I obtain fire except with a flint and steel, or,
at least, hardened iron; a flint and ordinary iron will not give an
available spark. Flints may be replaced by any siliceous stone, as agate,
rock-crystal, or quartz. Agate is preferred to flint, for it gives a
hotter spark: it is sold by tobacconists. A partly siliceous stone, such
as granite, will answer in default of one that is wholly siliceous. I
have been surprised at finding that crockery and porcelain of all kinds
will make a spark, and sometimes a very good one. There are cases where a
broken teacup might be the salvation of many lives in a shipwrecked
party. On coral-reefs, and other coasts destitute of flinty stones,
search should be made for drift-wood and drifted sea-weed. In the roots
of these, the pebbles of other shores are not unfrequently entangled, and
flint may be found among them. The joints of bamboos occasionally contain
enough silex to give a spark.

Steels.--The possession of a really good steel is a matter of great
comfort in rough travel, for, as I have just said, common iron is
incompetent to afford a useful spark, and hardened iron or soft steel is
barely sufficient to do so. Any blacksmith will make a good steel out of
an old file, if he h