close proximity to the fire. At one moment I thought the blaze had
caught it, and was about to caution you, but before I could speak you
had withdrawn it, and were engaged in its examination. When I
considered all these particulars, I doubted not for a moment that
_heat_ had been the agent in bringing to light, upon the parchment,
the skull which I saw designed upon it. You are well aware that
chemical preparations exist, and have existed time out of mind, by
means of which it is possible to write upon either paper or vellum, so
that the characters shall become visible only when subjected to the
action of fire. Zaffre[16], digested in _aqua regia_[17], and diluted
with four times its weight of water, is sometimes employed; a green
tint results. The regulus[18] of cobalt, dissolved in spirit of nitre,
gives a red. These colors disappear at longer or shorter intervals
after the material written upon cools, but again become apparent upon
the re-application of heat.

"I now scrutinized the death's-head with care. Its outer edges--the
edges of the drawing nearest the edge of the vellum--were far more
_distinct_ than the others. It was clear that the action of the
caloric had been imperfect or unequal. I immediately kindled a fire,
and subjected every portion of the parchment to a glowing heat. At
first, the only effect was the strengthening of the faint lines in the
skull; but, upon persevering in the experiment, there became visible,
at the corner of the slip diagonally opposite to the spot in which the
death's-head was delineated, the figure of what I at first supposed to
be a goat. A closer scrutiny, however, satisfied me that it was
intended for a kid."

"Ha! ha!" said I; "to be sure I have no right to laugh at you--a
million and a half of money is too serious a matter for mirth--but you
are not about to establish a third link in your chain: you will not
find any especial connection between your pirates and a goat; pirates,
you know, have nothing to do with goats; they appertain to the farming
interests."

"But I have said that the figure was _not_ that of a goat."

"Well, a kid, then--pretty much the same thing."

"Pretty much, but not altogether," said Legrand.

"You may have heard of one _Captain_ Kidd[19]. I at once looked on the
figure of the animal as a kind of punning or hieroglyphical signature.
I say signature because its position upon the vellum suggested this
idea. The death's-head at the corner diago