Book 10
45
But the last method which was hit upon by Cleoxenus andThe improved method of Cleoxenus and Democlitus. Democlitus, and further elaborated by myself, is above all things definite, and made capable of indicating clearly whatever is needed at the moment; but in its working it requires attention and more than ordinarily close observation. It is as follows: Divide the alphabet into five groups of five letters each (of course the last group will be one letter short, but this will not interfere with the working of the system). The parties about to signal to each other must then prepare five tablets each, on which the several groups of letters must be written. They must then agree that the party signalling shall first raise two torches, and wait until the other raises two also. The object of this is to let each other know that they are attending. These torches having been lowered, the signalling party raises first torches on the left to indicate which of the tablets he means: for instance, one if he means the first, two if he means the second, and so on. He next raises torches on the right showing in a similar manner by their number which of the letters in the tablet he wishes to indicate to the recipient.
