+43.+ The method of signalling by fire, which is of the highest utility in the operations of war, has never before been clearly expounded; and I think I shall be doing a service if I do not pass it over, but give an account of it adequate to its importance. Now that opportuneness is of the utmost moment in all undertakings, and pre-eminently so in those of war, no one doubts; and of all the things which contribute to enable us to hit the proper time nothing is more efficacious than fire signals. For they convey intelligence sometimes of what has just happened, sometimes of what is actually going on; and by paying proper attention to them one can get this information at three or four days’ journey off, and even more: so that it continually happens that the help required may be unexpectedly given, thanks to a message conveyed by fire signals. Now, formerly, as the art of signalling by fire was confined to a single method, it proved in very many cases unserviceable to those employing it. For as it was necessary to employ certain definite signals which had been agreed upon, and as possible occurrences are unlimited, the greater number of them were beyond the competence of the fire signals to convey. To take the present instance: it was possible by means of the signals agreed upon to send the information that a fleet had arrived at Oreus or Peparethos or Chalcis; but it was impossible to express that “certain citizens had gone over to the enemy,” or “were betraying the town,” or that “a massacre had taken place,” or any of those things which often occur, but which cannot be all anticipated. Yet it is precisely the unexpected occurrences which demand instant consideration and succour. All such things then were naturally beyond the competence of fire signalling, inasmuch as it was impossible to adopt an arbitrary sign for things which it was impossible to anticipate. [Sidenote: The improvement introduced by Aeneas Tactitus.]