2. All circles conceived to pass through the Poles of the world, intersecting the equinoctial at right angles, are, with respect to any point in the Heavens, called _Hour Circles_; and the _Circles of Ascension_, because the ascension of the Heavenly bodies, from a certain point, are by them determined. These circles are also, with regard to places upon Earth, called _Meridians_. [Sidenote: The _Brass Meridian_.] The _Meridians_ are commonly drawn upon the Terrestrial Globe thro’ every 15 degrees of the equinoctial, thereby making an Hour difference betwixt the places through which they pass. On the Celestial Globe there are commonly drawn but two of these _Meridians_, crossing the equinoctial in four points equidistant from one another, thereby dividing it into four quadrants; but the intermediate ones are here supplied, and also upon the Terrestrial Globe, by the brass circle on which they are hung, which, is therefore called the _Brass Meridian_, and sometimes only the _Meridian_, it serving for this purpose to all the points upon either Globe. [Sidenote: The _Hour Circle_.] There is also a little brass circle fixed upon this meridian, divided into 24 Hours, having an index moveable round the axis of the globe, to be turned to any particular Hour. The use of this circle is to shew the difference of time betwixt any two meridians, and is therefore called the _Hour Circle_. [Sidenote: _Parallels of Declination._] 3. All circles parallel to the equinoctial are, with respect to any point in the Heavens, called _Parallels of Declination_. So that, [Sidenote: _Declination North_ and _South_.] 4. The _Declination of any Point_ in the Heavens (as of the _Sun_, a _fixed Star_, or the like) is an arch of the meridian passing through that point, and intercepted betwixt it and the equator; and if the said point be to the (Northward/Southward) of the equator, it is called (_North_/_South_) _Declination_. [Sidenote: _Tropics_ and _Polar Circles_.] Of the parallels of declination, four are eminently distinguished by particular names, _viz._ The two _Tropics_, and the two _Polar Circles_. [Sidenote: _Tropic of Cancer; of Capricorn._] The tropics are on different sides of the equator each 23 degrees and 29 minutes distant from it; that which lies in the Northern Hemisphere, is called the _Tropic of Cancer_, and the Southern one, the _Tropic of Capricorn_. These circles are the limits of the Sun’s greatest declination, and are called tropics, because whenever the Sun arrives to them, he seems to return back again towards the equator. [Sidenote: _Arctic Circle._] [Sidenote: _Arctic Pole._] [Sidenote: _Antarctic Circle._] [Sidenote: _Antarctic Pole._]