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Mathematical instruments Book III, Chapter 9, Section 5a
5. From the Study of Books we shall proceed
next to those Noble Sciences which are gained
by their Instructions, which though but a Dead Letter,
yet gives Life to all manner of Arts. Now the Instruments which we shall treat upon, are principally such
as do measure forth to us both Place and Time; and
such as these are used and made for Astronomy, Astrology, Geometry, Navigation, the Art of Dialing, and
Clock-work.
Quadrant
XLVI. He beareth a Quadrant; the
Line and Plummet pendant. This is of
some called the Compass Quadrant, or Geometrical Quadrant, because the
same hath its circumference quarter round, and divided into 90 parts or degrees, being the fourth part of a circle; by the help of
this Instrument the height, depth and distance of places are taken and certainly known, and that by
the Plumb-line, or shadow of the Sun.
Quadrangle
XLVII. He beareth a Quadrangle, or a
Geometrical square, or Quadrant. The
Lines, or Degrees, & Plummet. In this Instrument there are three principal Lines, all the rest are
called the scales or degrees.
Jacobs Staff
XLVIII. He beareth a Jacobs Staff or a
Cross Staff; and a semi-Quadrant,
of some called a demi-Quadrant, or an Half Quadrant.
The Jacobs Staff, of some Writers called the
Profitable Rod or Staff. It is a Princely Instrument being set forth in its Perfection; it is a Rod four
square, being 3, 4, or 5 foot long, divided into inches all its length; having another cross peece on it, about
a foot or two long, having a square hole in the
middle, to move too and fro on the long Rod or Staff,
and made to tarry on any division, as occasion requireth. By the help of this Instrument, heights, lengths,
and breadths of places are taken, see chap.8. numb.169.
Semiquadrant
In the Base, is another sort of semi-Quadrant, or
Octodrant, which I have seen drawn in Mathematical
and Geometrical Tables of Instruments; it contains the
fourth part of a semi-circle, but of its use I have not
yet read.
Circular weather glass
XLIX. He beareth a Circular Weather
Glass. This is a Glass of two pieces, the
Shank, which is divided, is put into a Neck in the
midle of a Circular Glass, which being three parts
filled with a Water made by Art
(as Mr. Bate describeth pag.35.) and rarified in the head of the Glass,
both being well Luted together, and hung up by a
String, then the Water will in Cold Weather ascend
the Glass or Shank divided, to 8. 9. or 10 degrees, and
with heat it will descend the Shank and mount into
the horns of the round Glass.
Perpendicular weather glass
L. He beareth a Perpendicular Weather Glass set in a Frame. This is a
like Glass with a long shank, and a round head,
which shank is put through the hole of the Frame, on
the top, and so is fixed and Luted into another, at
the bottom or foot of the Frame, which is broader
below than above; the compound Water (as aforesaid)
being rarified in the head of the Glass, will ascend and
descend, according to the temperature of the Season.
There are double and trebble Glasses, made and
set in one Frame, and according to the composition of
the Water and rarifying the Air, some Waters will ascend in Cold, and others will ascend in Heat.
Sun dial
He beareth a Sun dial with its Gnomon, or Cock.
There are several sorts of Sun
Dials, some for Pillars or Posts, others for Walls, as
the following example.
Sun dial
LII. He beareth a Sun Diall for a Wall,
[with] the Cock or Stile, or Gnomon.
Untranscribed item(s)
Sun dial parts and terms (Of the sorts of Sun Dials, and the
Terms used about them.
[Cites ] Jo. Moxons Tutor to Astronomy and Geography, Lib.5. Art of Dialling)
Minute paces of a Clock
LIII. He beareth the Minute paces of a
Clock set on a Stand.
Meridian Spherical Dial
LIV. He beareth a Meridian Spherical Dial, of some termed a Planisphearal Sun Dial.
The use of this Geometrical Instrument, besides
the telling of the hour of the day by the height of the
Sun, is farther described by Mr Moxon in his Tutor to
Astronomy, Lib.5. to whose Works you are referred.
Equinoctial Dial
This is another sort of pendant Dials, which are
hung by the hand, and turned towards the Sun, that
by his Beams, darting through small Pin-holes made
for that purpose, the hour of the Day or Night may
be found. These are commonly called Equinoctial or
Universal Dials, and are most used by Sea-Men and
Travellers that oft shift Latitudes.
[The two drawings (not included on the plate) show an
equinoctial dial, folded and open.]
Clock
LV. He beareth a Clock, or an House
Clock; the two side Lids or Windows open,
[with] the Finger Board or Figure plate.
The Clock consists of two parts, viz. the Watch
part, which is always in motion, and the striking
part, which only goes about when it striketh the
Hours, of which several parts take the denominations
of them from the Watch, as in numb.57.
Hour glass
LVI. He beareth an Hour Glass.
Watch
LVII. He beareth a Watch, (or an Hour
Watch,) with its Cover open, and the Key in Base
Chained to the Watch.
Related text(s)
Watch parts
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