What is Navigation ?

• Navigation is that excellent Art, which demonstrateth by infallible conclusions, how a sufficient Ship may be conducted the shortest good way from place to place, by Table and Travers.

What are these infallible Conclusions ?

• Navigation consisteth of three parts, which being well understood and practiced, are Conclusions infallible, whereby the skilful pilote is void of all doubt to effect the thing purposed,
• Of which, the first is the Horizontal Navigation, which manifesteth all the varieties of the Ships motion within the Horizontle plain surface, where every line drawn is supposed a parallel.
• The second is a Paraboral or Cosmographical Navigation, which demonstrateth the true motion of the ship upon any course assigned in longitude, latitude, and distance, either particular or general, and is the skilful gathering together of many Horizontal Courses, into one infallible and true motion Paraboral.
• The third is a great Circle Navigation, which teacheth how upon a great Circle, drawn between any two places assigned (being the only shortest way between place and place) the Ship may be conducted and to performed by the skilful application of Horizontal and Paraboral Navigation.

What is a Course ?

• A Course is that paraboral line which passeth between place & place, according to the true Horizontal position of the Magnet, upon which line the Ship prosecuting her motion, shall be conducted between the said places.

What is a Travers ?

• A travers is the variety of alteration of the Ships motion upon the shift of winds within any Horizontal plain surface, by the good collection of which Traverses, the Ships uniform motion of Course is given.

What instruments are necessary for the execution of this excellent skill ?

• The Instruments neccessary for a skilful Seaman, are a Sea Compass, a Cross-staff, a Quadrant, an Astrolaby, a Chart, an Instrument Magnetical for the finding of the variation of the Compass, an Horizontal plain Sphere, a Globe, and a Paraboral Compass. By which instruments, all conclusions and infallible demonstrations, Hydrographical, Geographical, and Cosmographical, are without controlment of errors to be performed: But the Sea Compass, Chart and Cross-staff, are instruments sufficient for the Seamans use: the Astrolaby and Quadrant being Instruments very uncertain for Sea Observations.