What is the Sphere ?

What are the distinctions of the Sphere ?

Which are the greater Circles, and which the lesser ?

Which is the Equator, or Equinoctial ?

What is the use of the Equator ?

What is the Ecliptick ?

What is the use of the Zodiac ?

What are the Colures ?

What is the use of these Colures ?

What is the Tropick of Cancer ?

(Readers after 1754 will add 11 days to these dates)

What is the Tropick of Capricorne?

What is the use of the Tropics?

What is the Artic polar Circle?

What is the Antartic Polar Circle?

What is the Use of Artick and Antartick polar Circles?

What is the Meridian ?

What is the use of the Meridian ?

What is the Horizon ?

What is the use of the Horizon ?

Are these all the Circles appertaining to the Globe ?

There are other circles which are sired & do properly appertain to every particular Horizon, as Azumuths, Almicanter, the Artick, and Antarctick Circle.

What are Circles of Azumuth ?

What are Almicanters ?

Almicanters or Circles of Altitude, or parallel circles to the Horizon and are described upon the Zenith, as the parallels to the equator, are described upon the poles, of which circles there are 90 answerable to the distinctions of the quarta altitudo, which are the degrees contained between the horizon and zenith. These circles cannot be described upon the Globe, to be applyed to every horizon, but they are distinguished by the circular motion of the quarta altitudo, for if I desire to see the Almicanter circle of 10 degrees, by moving the quarta altitudo round about the horizon, the zenith degree of their quarter circle, doth shew the Almicanter desired, in what elevation soever.

What is the use of those two Circles ?

The Quarta altitudo performeth the use of both, by the quarta altitudo and horizon, the courses from place to place are known according to the true horizontal position, as hereafter shall plainly appear: it also sheweth the degree of Azimuth, and observed altitude of any celestial body, in what latitude soever: by the Quarta altitudo and Horizon, you may describe a paraboral Compass upon the Globe, the poles height is at all times thereby to be known, and the variation of the Compass is thereby likewise given, as hreafter in the practice you shall be taught.

What are the Artick and Antarctick Circles ?

Every horizon hath his proper artick or antarctick Circle, those horizons that have the pole arctick elevated above them, have their proper artick circle, and those that have the South pole elevated, have their proper antarctick circle, the quantity of which circle is according to the Poles elevation, for if the pole be much elevated, then is the artick circle great, for the Poles altitude is the semidiameter of their circle, if the Pole be in the Zenith, then half the heavens is the arctick Circle.

What is the use of this Circle ?

If the Sun, Moon or any Stars be within this Circle, they are never carried under the Horizon during the time of their abode therein, whereupon it cometh to pass, that such as travel far towards the north, have the Sun in continual view and those that inhabit under the Pole (if any so do) the Sun is in continual sight for six months together, because the six septentrional signs are within the Artick Circle, the Equator being in the horizon.

There is another small Circle, which is called Circulus Horarius, or the hour circle, to be annexed to the Meridian of the Globe, for the perfection of his use, this circle must be divided into 24 equal parts, or hours, and those again into such parts as you please for the better distinction of time: this circle must be fastened to the Meridian, so that the hours 12 must stand directly upon the edge of the Meridian, & the pole must be the center of this Circle, upon which pole there must be fastened an Index to move portionably as the Sphere (upon any occasion) shall be moved. There is also an half Circle, called the Circle of Position, which uth it serveth to no great purpose for Navigation. I here omit, and thus is the Globe fully finished for the perfection of this use.

What are the Poles of the World ?

What is the Axis of the World ?

The Axis of the World is a right line passing by the Center of the Sphere, & limited in the Circumference, about the which the Sphere moveth, and is therefore called the Axis of the Sphere;& as all lines commensurable are limited between 2 points or pricks, so is the Axis of the world, & those 2 limiting pricks are called the Poles of the World.

What are the Poles of the Zodiack ?

What is the Axis of the Zodiack ?

The Axis of the Zodiack, is a right line passing by the center of the Sphere, & limited in the circumference, whose limiting points are the poles of the zodiack, and his Axis is moved by the Sphere as are his Poles,

What are the Poles of the Horizon ?

There are two Poles of the Horizon, which are the limits of his perpendicular diameter being equidistant 90 degrees from all parts of the horizon, & are the extreme limits of all altitude, that Pole which is in the upper hemisphere is called the Zenith, and his opposite Pole is called Nadir, they are extended in the firmament, but not fixed in it, for they move never, but remain always stable in their proper horizon, which could not be if it were fixed in the firmament, for then should they be moved with the firmament as the rest are, by the help of these poles is found the Azumuth and Almicanter of any celestial body, for a quarter circle devided into 90 degrees, and fixed to the Zenith as is the quarta altitudo, being moved to any celestial body, doth by those deg. shew the almicanter or altitude of the same body from the horizon,& that part of the horizon which the quarter circle traces, is the Azumuth of the same body, always provided that the Zenith stand answerable to the poles elevation, that is, so many degrees from the equator, as the Pole is from the Horizon.