( *74 ) 
The Frame has two Parts, one a graduated Arch of 
30 Degrees, each Degree being fubdivided into fix 
equal Parts ; the other a Chord of an Arc of 6o°, di- 
vided into two equal Parts (at the Extremities and in 
the Middle of which are Holes or Stops for the La- 
bel) together making 90° or a Quadrant. 
The Index turns upon the Center of the Frame 
the whole Compafs of the Arch, and has three 
Parts ; viz. a Nonius Plate, an Eye-Vane, and 
a Tube. The Nonius Plate moves with the Index, 
and fubdivides each of the fmall Divifions of the 
Arch into ten equal Parts or Minutes. The Eye- 
Vane is to look through in forward Obfervations. 
The Tube is to fhew, when the Index is hori- 
zontal. 
The Label moves upon the Center of the Frame 
the whole Compafs of the Chord of the Arch of 6o°, 
having three fixed Stations thereon, at 30°, 6 0% and 
90% and contains two principal Parts j viz. a Lens, 
and a Lanthorn. The Lens is to form the Sun’s Image 
upon the Shield. The Lanthorn is neceffary in Noftur- 
nal Obfervations. 
The Shield is fixed in the Center of the Frame, 
and has three Parts ; viz. an Azimuth Tube, a Hori- 
zontal Tube, and an Axis, or in Backward Obfer- 
vations a Ray-Plate. The Hole in the Shield is to 
receive the Sun’s Image. The Azimuth Tube is to 
direct the Plane of the Inftrument perpendicular. 
The Horizontal Tube is to fliew when the Label is 
level. The Axis is to cut the Object in forward Ob- 
fervations. 
Rule 
