L 367 3 
the right-angled triangles a e C, K C L being fimi- 
lar, ae is to e C, as K L to C K ; but the error of % 
the right afcenfion anfwering to a e is to a e, as ra- 
dius to the cofine of the liar’s declination ; and C K, 
is to the moon’s apparent angular motion about the 
pole, in four minutes, as coline of moon s apparent 
declination, to radius. Whence, by compofition of 
ratio’s, and by equality, the correction of the moon s 
right afcenfion is to e E the apparent difference of 
declination of the moon and flar, in a compound 
ratio of the moon’s apparent motion, in declination 
in four minutes, to her apparent motion about the 
pole in the fame time, and of the fquare of the ra- 
dius, to the produCt of the cofines of the ftars and 
moon’s apparent declinations. 
Further it appears from the fcheme, that the 
moon comes later to C than to the horary circle paffing 
through the point of the wire (a) cut by a flar be- 
tween C and D, whofe parallel of declination fhe is 
approaching, and that fhe comes fooner to C than to 
the horary circle palling through the point of the 
wire (a) cut by a flar between C and E, whofe 
parallel of declination fhe is receding from, by the 
time the flar takes to defcribe a e ; and, therefore, 
the right afcenfion of the moon deduced immediately 
from that of the flar mud be too great in the fir ft 
cafe, and too little in the fecond cafe, by the fpace 
a e meafured upon the flar s parallel of declination. 
Laflly, to explain the manner of examining the 
deviation of the wires, from a perpendicular to each 
other, by obfervations of the liars ; let A B, fig. 2. 
reprefent the direCling , and E D the middle horary 
wire, deviating from C F, fuppofed perpendicular 
to 
