fine of DFQ - 
tracked leaves n 
of the Angle fubt ended by Two Objects, &c. 425 
, \ 
_ -- 1 1 from which 1 = fin . DOF being fub- 
m L 
“^S^ Eg ; or becaufe s = -v, n = 
Moreover, the* quantity I — L in the nafcent Fate of 1 — F and 
n 
m 
i — m 
and 
sl'rr. 
m 
. Making therefore in the 
■ v x 1 — w 
m 
Tl 
V = J', 
n—s = 1 ; we ihall have 
v' I — Vl 
general expreffion. contained in art, 26. 
a x v/~/ = /, and 7== = 
Lof.hiJ ~ -16 paX V I-/X i-2/+l6f'DXl-2/ +//W' =F Tflp X 17 I -m 2 X ^ i -p z 
-f- i 6 p 2 ‘vXi-p i -?n z + n-rp^mpxA l — m z x v' l.-~p z ~ - 16 pa X v' i-p 2 x 1-2/' + 
1 6 ft 1 v x 2 - 3/>“ — jw 2 + ip^tn^zzmp x %/ 1 - rn x y/i —p z ; and 
becaufe the fine of the obferved angle is 4^ x x 1 ~2p z , 
the error of the obfervation itfelf,. that is r 
hU =A “ ~ ' " WT " ‘ 
In this example the portion of the telefcope has been fup- 
pofed exadlly in the plane of motion ; fhould it be in- 
clined to that plane at a fmall angle, of which the verfed 
fine = v, the pofition of the reflectors- and the arc pointed to 
# 
by the index being correct, the general value of cof. ED will 
30. To 
give the error of the obfervation, or ED 
1 — 2 p 2 
* The nafcent value of 
1 — i* 
2 ss , ' -v X i-?n 2 +JXi-ffl 2 
: but n ~ — „ — J — 
• * — 1 — O ■ r> i 
wherefore 
x — s 
m 
. 2 : ' 
X' — ti* i—m z 
1 n — znn ‘ 
, when s and n are nearly — x. 
m 
•| Whan the pofition of the telefcope only is erroneous, the points F and G 
coincide; 
