Briefe Expositions of the Geometricall and
Astronomicall tearmes mentioned in this
Treatise.


 
A lyne is a length without breadth or deepnesse.
Lyne

A Superficies or Surface hath onely length and bredth
without deepenesse.
Surface

A plane is equally flat, contained within lynes, and doth
not bulke out or shrinke in at any place: and is saide to
be represented, when a lyke figure hath an absolute
lyke situation and constitution.
Plane

An Angle is the concourse of two or moe seuerall lynes
in one same poynt: And is giuen when the degrees
of the subtending arch thereof is knowne.
Angle

A right or square angle is when two lynes fall square one
vpon another, making all the angles framed thereby
equall.
Right 
angle

A Sharpe or acute angle is any angle that is lesse then a
square angle.
Sharpe 
angle

A Blunt or Obtuse angle is any angle that is greater then
a right or square angle.
Blunt 
angle

A Triangle is a Figure of three Corners or angles: And
is giuen, when the quantity of all the Angles and sides
are knowne.
Triangle

A Circle is a round Figure, made by the turning of a
lyne vpon a poynt fixed.
Circle

Circumfe­
rence
Arch
The Circumference of a Circle is the outmost edge or
lymbe of the Circle, being in all places equidistant from
the aforesaid fixed poynt. Any part of a Circumference
is an Arch; An arch is giuen, when the degrees contai­



ned therein are knowne.

The Centre is a poynt in the midst of a Circle, Globe, or
Spheare.
Centre

The dyametre of a Circle is the longest straite lyne
that can be drawne within a Circle, and it passeth
through the Centre from side to side: The halfe there­
of is the Semidiametre.
Diametre
Semidia­
metre


A great Circle is that which diuideth the world into two
equall parts. The edge or Lymbe thereof containing
360. equall parts or degrees. A Degree is therefore
1/360 part of a Circle.
Great 
Circle
Degree


The AEquator or AEquinoctiall  is a great Circle,
girding the world in the midst between the two Poles.
Equinoctiall.

The Zodiack is a great Circle broad and slopewise situ­
ate, bearing the 12 Signes. In the midst of which Cir­
cle is a lyne called the Ecliptick, from which the Sun
neuer swarueth.
Zodiack
Ecliptick

The Meridian is a great Circle passing through the Ze­
nith and Poles of the world, being alwayes permanent,
though the Sphere be moued.
Meridian

The Horizon is a great Circle, diuiding the world (accor­
ding to sense) into 2 equal parts; viz, the Superior seen,
or Diurnall Hemisphere; and the inferior vnseene, or 
Nocturnall Hemisphere.
Horizon

AZimuthes or Circles verticall, are great Circles, and
passe through the Zenith intersecting the Horizon with
right angles.
Azimu­
thes

Almicanterathes or Circles of altitude are Circles para­
lell to the Horizon: and are greatest, being neerest the
Horizon; and least, being neerest the Zenith.
Almican­
tares.



The Axis, or axeltree of the world is a lyne supposed to
passe through the Centre of the Earth: the extreames
or ends of which lyne are the Poles of the world: viz,
the North end the Pole artick, and the South end the
antartick.
Axletree

There is North Latitude, and South Latitude of places:  
For all places between the Equinoctial and the North
pole haue North Latitude; and between the Equinoc­
tiall and the South Pole haue South Latitude. 
Latitude 
of places.

The Longitude of the Earth is as the Circuit of the E­
quator in the Heauens. And is diuided into 360 euen
parts or degrees.

Any two places, being lesse then 180 degrees distant, haue
one same Longitude, if they be vnder one same Meri­
dian; Otherwyse they haue different Longitude.

Any two places hauing lyke Latitude (being both North,
or both South Latitude) are in one same Paralell.
Longitude
of places.

The verticall poynt or Zenith is a poynt in Heauen di­
rectly ouer our heads, and is the Centre or Pole of the
Horizon.
Zenith.

The Oposite poynt  is the Nadire.
Nadir.

The Paralax or difference of Aspect, of a Comet Planet
or other Luminary, is the angle caused by the inter­
section of the Lyne of the true Place and apparant
place thereof reckoned in the Firmament.
Paralax.



FINIS.