The mariners magazine, or, Sturmy's mathematical and practical arts containing the description and use of the scale of scales, it being a mathematical ruler, that resolves most mathematical conclusions, and likewise the making and use of the crostaff, quadrant, and the quadrat, nocturnals, and other most useful instruments for all artists and navigators : the art of navigation, resolved geometrically, instrumentally, and by calculation, and by that late excellent invention of logarithms, in the three principal kinds of sailing : with new tables of the longitude and latitude of the most eminent places ... : together with a discourse of the practick part of navigation ..., a new way of surveying land ..., the art of gauging all sorts of vessels ..., the art of dialling by a gnomical scale ... : whereunto is annexed, an abridgment of the penalties and forfeitures, by acts of parliaments appointed, relating to the customs and navigation : also a compendium of fortification, both geometrically and instrumentally / by Capt. Samuel Sturmy.

CHAP. XXV. How other Circles of the Sphere besides the Meridians may be projected upon Dials.

THe Projection of some other Circles of the Sphere besides the Meridians (though it be not necessary for finding the Hours, yet) may be both an Or∣nament to Dials, and useful also for finding the Meridian, and placing the Dial in its due situation, if it be made upon a movable Body, as shall hereafter be shewed.

The Circles fittest to be projected in all Dials for those purposes, are, the Aequator with his Tropicks, and other his Parallels, which may be accounted Parallels of Declination, as they pass through equal Degrees, as every 5 or 10 of Declination: Or Parallels of the Signs, as they pass through such Degrees of Declination as the Sun declineth when he entreth into any Sign, or any notable Degree thereof; or Paral∣lels of the Length of the Day, as they pass through such Degrees of Declination wherein the Sun increaseth or decreaseth the Length of the Day by Hours or half Hours.

Also the Horizon, with his Azimuths and Almicantars, are as an Ornament to Horizontal and Vertical Dials, and are likewise useful for projecting the Aequator and his Parallels in all Dials. My intent is to be brief in this Treatise of the Furni∣ture here following, because I will have a President of some other Country Dials: I shall therefore think it sufficient if I shew you one way to furnish any Dial with the Circles of the Sphere, leaving you to devise others which I could have shewn.