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.

The chiefest vses of the Mariners Carde. Chap. 31.

THe chiefest vses of the sea Card are these foure here following:

The first is to know thereby how that place where∣unto you would sayle, beareth from the place or Port from whence you set off, or depart. And that is to be knowne by the lines of the Mariners Compasses painted in the Card in this manner following: Take a paire of Compasses and hauing ope∣ned them, set the one foote thereof in the very place from whence you depart, and the other foote in the next line of that Compasse which is nearest vnto your place of departing, I meane such line as doth most rightly direct you to the place to which you would go, and your Compasse being opened at the fit widenesse to serue that line, draw them from the place of your departing vnto the place whereto you would go, suffering that foote of the Compasse which standeth vpon the line of the winde whilest you draw it for∣ward, not to swerue one iot from that line, and that line will ey∣ther rightly direct you to the place assigned or fall short thereof, or else ouerrech the same, if it fall short, then take another line nearer to the place from which you departed, and if it ouerreach, take some line that is further off from the place of your depar∣ting,

and hauing found a line that pointeth directly to the place, consider what winde or rombe it is, for by that winde the place assigned beareth from you, and the rombe or winde opposite to that is the winde whereby you haue to sayle.

The second vse is to knowe by the Carde how farre the place whereto you go is distant from the place of your departing, which is done by helpe of the skale or trunke set downe in the Carde thus: Take the iust distance betwixt the two places with your compasses by setting the one foote in the one place, and the other foote in the other place, and apply that widenesse of the compasses to the skale or trunke, and the trunke wil shew how many leagues the one place is distant from the other, and if the distance betwixt the places be longer then the trunke, then take first the length of the trunke with your Compasses, and looke how many times that is contained in the space betwixt the two places, and if there doe remaine any odde measure, then hauing taken that odde measure with your compasses by setting thē at such widenes as is answe∣rable to that odde measure, apply that widenesse to the first part of the trunke, so shall you know the iust measure of the whole. And this rule serueth to take the true distance of any other two places whatsoeuer set downe in the Card.

The third vse is to know by the Card what Latitude or alti∣tude of the Pole any place set downe in the Carde hath, which is done by helpe of the line of degrées of Latitude, otherwise called the Graduation of the Carde in this manner following. Set the one foote of your compasses in the very place whereof you would know the Latitude, and the other foote in the line of East & West, which is next vnto that place, and kéeping that foote still vpon that line, draw your compasses forward vntill you come to the line of degrées, and marke what degrée of the said line the foot of the com∣passe which was first set in the place doth crosse or touch, for that is the degrée of Latitude for that place, numbring from the lowest degrée of Graduation vpwarde, so shall you finde the Latitude of Lisbone in Portingale by Mercator his vniuersall Carde, and by the Carde set downe in Martin Cortes booke, and also by Me∣dina his Carde drawne in his booke of Nauigation to be 38. de∣grées 30. minutes and somewhat more. But by the Tables of Ptolomie you shall finde it to be 40. degrées 24. minutes, and

by Appian his Tables to be 39. degrées and 38. minutes.

The fourth vse chanceth when you are driuen out of your right course by stormes or tempest, which stormes how to foresée and to prognosticate, is plainely taught by Martin Cortes in the 19. Chap. of his second booke. Also you may be driuen by force of con∣trary windes, by surging of the sea, or by ouerthwart tides, cur∣rants, & such like impediments, so as you can not lay your course right to the place assigned, for remedy whereof you must séeke in what place you are, & to note the same in your Card which as the Mariners terme it, is to make a pricke in the Carde, which to doe truely in time of néede many things are to be known & well obser∣ued and kept in memorie. First to know what latitude the place from whence you first departed hath, then to kéepe in minde what way your shippe did make good at euery shift of winde, that is to say, how many leagues, and in how long time you sayled by eue∣ry seuerall winde: and then not knowing well where you are, nor how farre you are distant from the place whereto you would go, learne to knowe by helpe of your Astrolabe or crosse staffe, in such sort as is before taught, the altitude of the Pole in that place where you are, which if you finde to be all one with the La∣titude of the place of your departure, then you may assure your selfe that you haue sayled by the line of East and West with∣out altering your Latitude, but if you finde the Latitude of the place where you are, to be more or lesse then the Latitude of the place from whence you departed, then resort to your Card, and take two payre of Compasses opened at such widenes as the one foote of the one Compasse may stand in the place from which you departed, and the other foote of the same Compasse to stand in the line of the rombe whereby you sayled: and let the one foote of the other Compasse stand in that degrée of Latitude which you last found, and the other foote of the same Compasse in the next line of East & West, and holding the Compasses so ordered in ech hande one paire: draw them both so as they may méete together, taking good héede in drawing them, that the foote of that compasse which was placed in the line of the winde, may at no time swarue from that line, nor the one foote of the other Compasse to swarue from the line of East and West, wherein it was first pla∣ced, and whereas the two féete of those Compasses doe méete,

that is to say, that foote of the one compasse which was drawne from the place of your departing doe méete with that foote of the other compasse which came from the degrée of Latitude last found, where these two féete (I say) doe méete, there make a pricke or marke in your Carde, for that is the place where you shippe is at that instant: And from thence you must take your right course a∣gaine to the place whereunto you would go. But because it is ne∣cessarie aswell at this time as at all other times, to knowe what way your shippe hath made, and that the same is not in mine opi∣nion, so plainely nor so commodiously taught by any one that I haue read, as by Michaell Cogniet, I minde therfore in the two chapters next following to set downe his way not only how to find out the way of your shippe when you saile South and North vn∣der one selfe Meridian, or in any other place where you are to change in your gate the latitude or altitude of the Pole, but also how to finde out the way of your shippe in sayling right East and West, without changing the altitude of the Pole, which way as he sayth, was neuer heretofore knowne to any Pylot but to him selfe first author and inuentor thereof.