as are terminated by Planes , &c. 
8°9 
where ^ = (3a.' ( 1 + r*) , v = 1 4- ya 2 ( 1 -f- r 2 ), ^/= ( 1 -f. r fs ), 
v* 1 -j- y# 2 ( 1 -j— r 1 2 ) , 
4r/3a % 
? = -=i^- L [Sjg 4- v/- + 1 ) 
p ( i + y^*) v v' i* r- 
or 
V-v(l+ 7 «.*) 
arc 
(sine 
v — M 
v ^ 
4r , (3a s ’ 
as v is positive or negative, 
v' »* ( 1 -j- y a *) ' fit, 
L f^= + + l), 
v' (i -j-y» 2 ) 
arc 
(sine - - -L A | as / is positive or negative. 
S s 
MDCCCXH. 
