As to the practical side of navigation, Bourne exhorted his mariners to remember that the earth is a globe and not a “platforme,” as “generally the most parte of the seamen make their account.” The meridians, he reminded them, grow narrower towards the two poles. If one had occasion to voyage northward it were better to sail by the globe, he suggested. Therefore you should keep a perfect account of the ship’s course. Then resort to your globe and consider what place and parallel you are in (by means of the sun at day and the stars at night). Knowing where you are, set your globe to the elevation of your pole, and then turn to the place of your zenith and seek the opposite of it in your parallel, for then you know that in the same parallel is your east and west line. Then the just quarter of that circle to the pole must be divided into the eight points of your compass, doing so likewise on the other side. From the southern voyages the “plats or cardes for the sea” were recommended. Bourne strongly advised against painting their compasses with so many colours on these charts and so many flags on the land, but bade them use the vacant places left on the paper for better objects, such as the time of high water at certain states of the moon, and the elevation of the land, in order that the appearance of the latter might not be mistaken. The use of sea cardes for navigating during long voyages he regards as very necessary for three reasons: they show you (1) how one place bears from another; (2) the distances between the places; (3) in what latitude any place is. But the master or pilot of the ship is also to bear in mind the effect of tides, currents, the surging of the sea or scantiness of the wind, which might put the ship to leeward of her course. Also in long voyages the wind might shift ahead, so the mariner must keep a perfect account of his courses and mark each new course on the chart, and pay regard to the “swiftnesse” or “slownesse” of the ships. If the weather be clear he was to take the true altitude of the pole, which will correct the ship’s course and give “a very neare gesse” how the port of destination bears and how far.