(*7t) 
being fet, as the Sun rife's, the Horizontal Bubble on 
the Index will not quit theopenEnd of the Tube, or 
flop between the Ends, but hang there, or leave it after 
the Azimuth Bubble and Sun’s Image have been regu- 
lated, which will require the Index to be continually 
moved down in order to keep the Quadrant fet. When 
;the Sun is up, or on the Meridian, the Quadrant 
will remain fet for fome time ; and on the Sun’s falling, 
the Horizontal Bubble will have a reverfe Tendency 
inclining or running wholly to the enclofed End of the 
Tube. 
To tale the altitude of the Sun or Stars by a for- 
ward Obfervation . 
In this Method, the Lens and Tube on the Index 
are difregarded. Hold the Quadrant vertical, and 
looking through the Eye-Vane, direft the Axis or 
upper Edge of the Shield to the Sun or Star; if the 
Axis cut the Sun or Star at the fame Infant that the 
Bubble in the Horizontal Tube on the Shield quit the 
open End, the Altitude is then truly taken, and the 
Quadrant fet. But if it fhould leave the open End 
of the Tube before the Axis or upper Edge of the 
Shield cut the Sun or Star, then the Eye-Vane (or 
which is the fame, the Index) inuft be Aid down - and 
if it remain at the open End, or quit it when the Axis 
is above the Sun or Star, moved up until the Quadrant 
is fet. In continuing the Obfervation for a Meridian 
Altitude, as the Sun or Star rifes, the Bubble in the 
Horizontal Tube will always quit the open End of 
the Tube before the Axis cut the Object ; fo that to 
keep the Quadrant fet, the Eye-Vane tnuft on every 
fuchAlteration be conftantly moved down 5 while the 
