The invention of telegraphic communication has proved of the greatest utility in modern warfare, both for despatch and security. In ancient times, the bearer of messages had both an important and dangerous duty to perform, and one which was very uncertain in its execution. A singular and ingenious method of communication, is attributed to Hystiæus, who, desiring to write to Aristagoras, shaved the head of his trustiest servant, and wrote upon his scalp, in certain brief characters, what he would impart to his friend, and keeping him in his house till the hair was grown as thick as before, then sent him on his errand.[10] By the policy of Gracchus, the Roman general, the Campanian city of Casilinum was for a considerable time prevented from falling into the hands of Annibal. Gracchus was encamped in the vicinity of the city, but, though the garrison was reduced to the most dreadful extremity by famine, many of the soldiers having been driven to commit suicide, he did not dare to make a movement to relieve the besieged, the dictator having imperatively enjoined him not to stir from his position. In this emergency he had recourse to stratagem. The Vulturnus ran through the place, and Gracchus resolved to make it the channel by which to convey succours. “He therefore,” says Livy, “collected corn from all parts of the country round, and having filled therewith a great number of casks, sent a messenger to Casilinum to the magistrate, desiring that the people should catch the casks which the river would bring down. The following night was passed in attentively watching for the completion of the hopes raised by the Roman messenger, when the casks, being sent along the middle of the stream, floated down to the town. The same stratagem was practised with success on the following night and on the third; but the river being afterwards rendered more rapid by the continued rains, an eddy drove them across to the side where the enemy’s guards were posted, and they were discovered sticking among osiers which grew on the banks. This being reported to Annibal, care was taken for the future to guard the Vulturnus with greater vigilance, so that no supply sent down by it to the city should pass without discovery. Notwithstanding which, quantities of nuts being poured into the river at the Roman camp, and floating down to Casilinum, were stopped there with hurdles. The scarcity, however, at last became so excessive, that tearing off the straps and leathern coverings of their shields, and softening them in boiling water, they endeavoured to chew them; nor did they abstain from mice or any other kind of animal. They even dug up every sort of herb and root that grew at the foot of the ramparts of the town; and when the enemy had ploughed up all the ground round the wall, that produced any herbs, they sowed it with turnip seed, which made Annibal exclaim, ‘Am I to sit here before Casilinum until these grow?’ Although he had