( 730 ) 
that with “7 includes an angle «, (0) O (a) the secant line between 
KE and WV: the azimuth of a secant plane (P,Q) be measured from 
(O) positively opposite to the direction of the hands of a clock. If 
Pe oe Spe a 5 
one indicates the globe octants (0) (=). @ (ar) , (2) (5e) and 
3 ; 
(Gr (O) respectively by the numbers 1, 2, 3, and 4, in so tar as 
they lie above the equatorplane, by 5, 6, 7, and 8 in so far as they 
lie below it, then one can deduct from the figure with regard to 
the sign of / in the various octants what follows. 
Jt 
MO ea at and if the pole g of the secant plane Q lies in the 
first octant, A becomes = / AOB>0. In the opposite 7" octant 
one finds for the secant plane (g',Q) a negative apparent angle; if Q 
and Q’ coincide, so that the distance of the poles is g:q’ =a, then 
h, becomes = —h. 
If the pole of the secantplane lies in the 2"¢ oetant, then / becomes 
<0; if one applies Q, with regard to the plane 0 (2 symmetrie 
ally“ with Q then A, becomes again = / A,OB, = —h(7Z AOB). 
Tt 
If at last the pole lies in the plane O =), then 4 =O indepen- 
dently of the value of o. 
In the octants 3 and 4 the pole of the secant plane moves exclu- 
sively within the obtuse angle /’;]’. If with a constant value of g, 
we substitute for the pole (p) of the plane (/?) successively all the 
Ld 
values of o between 0 and ae it appears that for o=0, h=0O; 
if o becomes > 0, as in the plane (p’//), h becomes = / C,OD<0; 
this negative angle becomes larger if 5 increases till the pole lies in 
: mr ' 
p, and h has become = “ COD = — — . Now the negative angle 
n ; ae 
surpasses the value Sa and is consequently measured positively 
x 
as far as O (” <6 al 
. ; I 
By construction the point p can easily be found, because ~ Cp = An 
From (1) follows, that here 
cot h cos 9 = 0 = cos 6 cot a + sun Oo sin O 
