M. Blundevile his exercises containing sixe treatises, the titles wherof are set down in the next printed page: which treatises are verie necessarie to be read and learned of all yoong gentlemen that haue not bene exercised in such disciplines, and yet are desirous to haue knowledge as well in cosmographie, astronomie, and geographie, as also in the arte of navigation ... To the furtherance of which arte of navigation, the said M. Blundevile speciallie wrote the said treatises and of meere good will doth dedicate the same to all the young gentlemen of this realme.

To knowe by helpe of a little Table made according to the Mariners rule touching the 8. principall rombes, shewing how and when the Lodestarre is either aboue or beneath the Pole, that you may knowe thereby the true altitude of the Pole in taking the height of the Lodestarre with your Astrolabe or crosse staffe. chap. 40. Chapter 40.

TO know this you must alwayes haue due considera∣tion of the two guards of the little Beare, for when those guards are iust Southwest from the Lode∣starre, then is the Lodestarre at his highest in the verie Meridian, and therefore it is right aboue the Pole, and when those guards be iust Northeast from the Lodestar then the Lodestarre is againe in the Meridian at his lowest, and thereby right vnder the Pole, and in both places his distance from the Pole is but thrée degrées and a halfe, as Cogniet saith, accor∣ding to which account he setteth downe this Table following.

This Table is diuided into two collums, whereof that on the left hand contayneth the eight principall rombes or windes, and that on the right hand contayneth the degrées and minutes of di∣stance of the Lodestarre from the Pole, being either aboue or be∣neath the Pole.

If the guards be	The rombes or windes.		The degrees and minutes of the declination of the Lode∣starre from the Pole.
West. Southwest South Southeast.	Then the Lodestar is	1 ½ 3 ½ 3 0 1 0 Aboue the Pole.
East Northeast North Northwest	1 ½ 3 ½ 3 0 1 0 Beneath the Pole.

This table differeth in one point from the Mariners common rule set downe as well by Medina, and by Martin Cortes, as also by William Boorne touching the guards, for they all appoint but halfe a degrée of declination of the North starre from the Pole, the guardes being either in the rombe Southeast, or Northwest, to both which rombes Cogniet appointeth one whole degreé of de∣clination. The vse of which table in seeking to know, the eleuati∣on of the Pole is thus. First, hauing taken with your Astrolabe the altitude of the Lodestarre aboue your Horizon, obserue imme∣diatelie in which of the 8. former rombes his guardes be. For if they be in any of the 4. vpper rombes of the Table, then you must subtract from the height of the Lodestarre taken with your Astro∣labe, so much as is set downe for that rombe in the collum on the right hand of the said table, and the remainder shall be the true al∣titude of the Pole, but if the guardes bee in any of the foure nether rombes, then you must adde so much to 〈◊〉〈◊〉 height of the Lodestar, and the summe thereof shall be the altitude of the Pole. But be∣cause this table serueth only for the 8. principall winds and for no more. Cogniet therefore setteth downe the making of a twofolde instrument, whereby you shall not onely know (as he saith) how much the Lodestarre is aboue or beneath the Pole in euery other rombe as wel as in the 8. principall rombes, but also you shall know therby the true houre of the night more exactlie than the Nocturlabe of Munster or Appian doth shew.