new Syfetn of Wires in a ‘Telefcdfie. 351 
thofe Hars pafs it. N. B. This be- 
ing in time muft be converted into 
* degrees , and multiplied by cofine of 
declination as ufual, to give the true 
difference in declination between the N 
liars. 
. * 
And the fame cxpreflion, viz. 
2 * x f m> q — the difference in JK between thofe two 
R x tin. a 1 
points ; to be applied as a corredlion 
to the obferved times. 
The fame may be done by the larger intervals m and y, only 
by fubllituting a ~q in the place of a + q, thus : 
2 a 111 ^ U, X fi n « n 0 /. -1 • *11* ■ 1 
— u- ■ — — - - x col. q — dirrerence in decimation as above ; 
R x fin. a 2 
or x fin. q — afcenfional difference. 
If the liars differ too much in declination to come within 
the expreffion above (as N° 2. and 3.) then the differences of 
the angles D and E in declination and right afcenfion may be 
found thus: 
— ^ C ° f ’ q = difference in declination between D and E J 
2 . b x fin. q 1 • c f < i » ry’ 
■ =2 their alcennonal dirrerence ; 
R 
and the difference of each liar from its refpe&ively nearelt 
angle of the rhombus, may be deduced by the former expref- 
fion, leaving out the confideration of the other Har, thus : 
2_ . »xfm. a + q CQ p _ difference of the Har in declination 
R x im. a 1 
from its nearell angle. 
and . . . x fin. q = its difference in right afcenfion. 
The application of thefe formulae is very eafy: for having 
0 und if you fet down its cofine in one column for declina- 
Yol, LXXV. A a a 
tiorij, 
