C I0 3 ] 
in the focus of the eye-glafs parallel to one another* 
and to the plane of the quadrant. If they were put 
at fuch a diftance as to divide the diameter of the 
field of view into three equal parts, it might be as 
convenient as any other interval. In this manner 
wires were placed in the telefcope by Mr. Hadley, 
as appears by his account of the inftrument in 
Philof. Tranf. N° 420. Thefe wires are to be ad- 
jufted parallel to the plane of the quadrant, by turn- 
ing the eye-tube round about which contains the 
wires, till they appear parallel to the plane of the 
quadrant. The axis of the telefcope, by which is 
meant the line joining the centre of the objed-glafs 
and the middle point between the two wires, is to be 
adjufted parallel to the plane of the quadrant by 
either of the two following methods. 
lft method. When the diftance of the Moon 
from the Sun is greater than 90 degrees, by giving a 
fweep with the quadrant and moving the index, bring 
the neareft limbs to touch one another at the wire 
neareft the plane of the quadrant. Then, the index 
remaining unmoved, make the like obfervation at 
the wire fartheft from the plane of the quadrant; 
and note whether the neareft limbs are in contad as 
they were at the other wire : if they are, the axis of 
the telefcope is parallel to the plane of the quadrant 
but if they are not, it is inclined to the fame, and 
muft be corrected as follows. If the neareft limbs 
of the Sun and Moon feem to lap over one another 
at the wire fartheft from the plane of the quadrant, 
the objed end of the telefcope is inclined from the 
plane of the quadrant, and muft be altered by the 
adjuftment made for that purpofe : but, if the neareft 
limbs 
