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.

How to know the height of any starre at any houre, without seeing the starre, and thereby to find out in the firmament all the starres that be described in the net, and are to bee seene with the eye. The 20. Proposition.

LAy the labell to the houre supposed vpon the limbe of the mater, and then bring the place of the sunne for that day to the Fiduciall line of the labell, and there hauing stayed the Rete, bring the Fiduciall line of the labell to the tippe of the starre whose al∣titude you séeke, and the labell will shew you vpon the limbe of the Mater how many degrées that starre is distant from the South. Againe by counting vpon the label, the degrées contained betwixt the point of the labell, and the tippe of the said star you shall haue his declination, which is North or South according as the starre is Northerne or Southerne. Then bearing in mind, aswell the stars distance from the South, as also his declination, work thus, Bring the Finitor to your Latitude, and vpon the stars Parallell or Circle of declination in the Mater count from the limbe of the Mater, the distance of the starre before found, and marke what Al∣micanterath crosseth that point, for there is the altitude of the star at that instant, and the Azimuth which cutteth that point, sheweth in what part or coast of heauen the starre is at that present. And remember to séeke the Parallell of the starre on that side of the Mater either on your right or left hand, so as it may fall amongst the Almicanterathes, for otherwise you shall not finde that you séeke. As for example the 26. of October 1591. at nine of the clocke at night, you would know the height of the first star of the Rams horne called Cornu Arietis the Sunne being then in the 12. de∣grées and 12. minutes of Scorpio. Here after that you haue laid the labell to the houre supposed, and brought the degrée of the

Sunne for that day to the Fiduciall line of the labell, and stay∣ed the Rete there, bring the labell to the tippe of the starre in the Rete, and the labell will shewe in the limbe of the Mater how many degrées the starre is distant from the South, which you shall finde to be 28. degrées and 30. minutes, and the declination of the sayde starre being counted vpon the saide labell, to be 18. degrées, then kéeping those two numbers in minde, bring the Finitor to your Latitude supposing the same to be 52. degrées, and there staying the Rete, séeke for the Parallell of the starre which is 18. degrées on your right hande, and vppon that Pa∣rallel count by the Meridians from the limbe inwarde, the stars distance from the South, which was 28. degrées 30. minutes, and you shall finde that the 49. Almicanterath cutteth that point, so as you may conclude that the altitude of the starre called Cor∣nu Arietis, was at that houre 49. degrées, and that the 47. Azi∣muth doth also passe through that point which sheweth that the starre is 47. degrées from the East towardes the South, which according to the Mariners account is Southeast, and somewhat more to the Southward. Now to finde out the saide starre in the firmament, if it be a starre light, you haue no more to doe but to lay the Diopter of your Astrolabe at that altitude, and to turn your face towardes that coast (that is to say) Southeast and somewhat more to the Southwarde, and the next bright starre which answereth in that coast to that altitude is the starre which you seeke.