934 _ AN accouNT OF THE 
As the second number is so small we may for P* substitute it’s ap- 
3 4, 3 3 ° eyy, 
proximate value —— i _ which will give, 
B® Cos 
Perea ee 
Pp Cos L 3R'* p? Cosh. 
Ir is evident that the second member is merely the cube of the first 
divided by 3 R°: although this makes the calculation sufficiently simple, 
yet Thave given a table, (Table 11), from which it may be taken by 
inspection, the areument being the approximate value of P, or that found | 
by the first part. p Cos L is giyen in Table 10, 
To shew the use of the formula take the last example. 
flog. «4, 5:882,421 
Log. f, 0:000,191 Table 5, 
p, Cos LL, Ar. Co, 8:057,697 Table 10, 
iy 
87158 5:940,309 aN 
Correction to 8716,- 5:2 Table 11, 
oo, 
Long, 87166 = ‘2 25 10-G true to 2. 
‘Ture now remains only the Azimuth, and to determine this we have, 
‘Tang. PB: R :; sine A B Cot. P A B, or employing the proper notation, 
Cot. LE: R;: sine >: Cot. (90 — dz.) — tang. dz, 
area 
Sne@' and as 2 i = tangent IL this is equivalent to sine 
Tang. dz. == 
$ tangent LL. 
A ae ee ae 
