I now quote Robert-Houdin's account of

CARD TELEGRAPHY.

Although there are 32 cards in the game of Piquet, all of them
may be designated by twelve different signs, namely, eight for
the nature of the cards, and four for the colours.

At Ecarte, the number of the signals is still less, as it is only
the figures that require indication: but to make these
indications it is necessary to execute a sort of pantomime,
according to certain authors, such as blowing the nose, coughing,
drumming on the table, sneezing, &c. Such evolutions, however,
are totally unworthy of your modern Greek, and would soon be
denounced as gross fraud. The signals which he employs are only
appreciable by his confederate,--as follows:--

If he looks

1. At his confederate, he designates A king.

2. At the play of his adversary . . . A queen.

3. At the stake . . . . . . . . . . . A knave.

4. At the opposite side . . . . . . . An ace.

And whilst he indicates the nature of the cards he at the same
time makes known the colour by the following signs:--