No Vessel can enter these Ports, unless it touches at _Istria_, and takes a Pilot on Board, or unless, on approaching to the Ports, it wait for the Towers of the Admiral to tow it up. These Officers do not immediately depend upon the Magistrate, but are obliged, however, not to neglect any of his Rules, nor to mix with any Vessel, even free or cleared, unless by the Magistrate’s Leave; to make use of tarred Cables, or Cables of [Transcriber’s Note: an intentional blank space was left here in the original] in the towing Vessels in, in order to avoid all Communication, and to direct the Captain of every suspected Vessel to hoist up on the Mizen Mast a particular Signal; so that, by Means of the Spies, who are continually on the High Tower of St. _Mark_ to discover any Vessels that approach, such Vessel is immediately known to be a Vessel subject to perform Quarantine. As soon as the Vessel is discovered, the Magistrate has Notice, and all the Officers belonging to him; the Chief of whom instantly dispatches the _Guardian_ (whose Turn it is) to meet it and go on Board, and guard it during the Term of Quarantine. The Magistrate has Sixty of these Guardians in his Service, whose Duty it is, by Turns, either to go a-board any Ship, or to the _Lazarettos_, to superintend the Purification of Merchandizes, or the proper Quarantine of Persons. Their Duty, in general, is to see that all the Rules are observed concerning the Precautions and Purifications: Their Office is dangerous and delicate to the last Degree; they have a particular daily Appointment, which they have also from those concerned in the Ship or Cargo, besides their daily Provisions; and they answer with their Life any Contravention to the Rules that they should suffer to take Place, or dare to have any Hand in. The Guardian then being dispatched to meet the Ship, he either meets her and goes a-board her out at Sea with the Admiral’s own Boat, when there is any Doubt that it may be come from infected Parts; or he waits for her in those Waters where the Admiral, or his Towers, bring her to cast Anchor; the Places being different according to the different Size of the Ships, or the different Inspections under which they fall; as, for Vessels that are very heavy, and sink deep in the Water, deeper Canals are assigned; for those coming from Places which, their Passes shew, were infected, or on Board of which there are any Appearances of the Plague, Canals are assigned more remote, even twelve or fourteen Miles distant from the City; and in that Case they are guarded by the publick Galleys, or Barks armed with Militia in Proportion to the Number of Vessels at one Time in that Quarantine, or according to the Quality of the Suspicions had of them, in order to prevent any Person from entring into these Canals, or any Thing being brought clandestinely out of them.