This we should scarcely be able to do, even if we had plenty of ships to spare, and were freed from our present necessity of exhausting all our strength upon the blockade. For it is already difficult to carry in supplies past Syracuse; and were we to relax our vigilance in the slightest degree it would become impossible. The losses which our crews have suffered and still continue to suffer arise from the following causes. Expeditions for fuel and for forage, and the distance from which water has to be fetched, cause our sailors to be cut off by the Syracusan cavalry; the loss of our previous superiority emboldens our slaves to desert; our foreign seamen are impressed by the unexpected appearance of a navy against us, and the strength of the enemy's resistance; such of them as were pressed into the service take the first opportunity of departing to their respective cities; such as were originally seduced by the temptation of high pay, and expected little fighting and large gains, leave us either by desertion to the enemy or by availing themselves of one or other of the various facilities of escape which the magnitude of Sicily affords them. Some even engage in trade themselves and prevail upon the captains to take Hyccaric slaves on board in their place; thus they have ruined the efficiency of our navy.