Manuscripts and Special Collections

Pw A 2090 : Notes giving instructions on the conduct of secret correspondence; n.d. [1687-1688]

When I send you any letter directed Mons[ieu]r Jan
van Loen Vienne, be pleased to open it, & if you find
onely a Gazette enclosed, or a few lines of any com[m]on
matter, or a longer letter, with a Postscript ending with
an &c, in any of these cases you will have occasion to
make use of the under written directions, that is to say,

Put into fair water soe much as you please of the
Powder of white Coperose, the stronger you make this the
better, & herewith wash the blank parts of the letter,
rubbing it on with the Feather of a Pen, & imediate
-ly you will see the writing appear. Bee pleased to let
one side dry, e're you wash the other, or both sides being
wett at a time, the writing will not be soe visible as you
will find it, when the paper is dryed.

And when the Prince is pleased at any time, or has occasion
to answer, such letters with more freedom, than he shall
think fit to doe in Inke, if he is pleased to direct you to
hon[ou]r me with such Com[m]ands, I have a Private direction
given me by my L[or]d D- whereby to send them, written
in the invisible liquor, w[hi]ch the Coperose brings forth.

Bee pleased to observe the Coperose is Poyson.