a first Approximation to the Orbit of a Comets 167 
46* 
6* — ^ X 1*001774 = + o*oooo57« 
Because the last value of p is too great, let p = 0*329 : then 
r' = 0*864426 
r'*z= 0*695012 
V = 0774351 
b* = 0*010736 . 
a' — 3-118876 . . . log. 0-4939875 
log. a = 0-2469938 
b' — ^ X 1*001774 = — 0*000007. 
By comparing the two last errors we finally get p = 
0*32911: then 
7**'= 0*864412 
r' = 0-694945 
V = 0-774307 
b*= 0*010743 
a" = 3-118714 .. . log. 0-4939760 
log. a = 0*2469880 
4G* 
b* — ~ X 1*001774 = 0. 
From the values just found, we get 
log. r — 9*9683604 
log. f =z 9*9209752 : 
and the angle contained by r and r', the cosine of which is == 
will thence be found = 2° 31' 35". These quantities are 
sufficient for determining the parabola described by the comet ; 
and as they are the immediate results of the method, the fairest 
way of judging of the exactness of that method, seems to be, 
to compare them with the true values calculated from the 
