ao 5 
1S 
) 
le 
iC 
(391) 
which, applied at the point N (y — 0) and at the points À and A, (v/z = d), 
must furnish two equal values of ^ b: 
k k 
in b C b 
Ab: Abu + > Z anco Z x Abi T4. 
b 
Azat Y A za | == 
/ 
N | 
T 
1 
- - 
k 
e XV b b 
rm MS d 
- 
in which 
bis: 
es 
  
„ / ” / ui ; Nb 
e." t * blé re) "|A -Ab) + y DEN 
2 
og oping Fgh qn 
= 2 (A b1 — À Di) +33 Az + z B AME LM J' 
- 
2. Inclination si. of the air base to the horizon and the vertical component 
bz.. — The difference © = (ax — ax—1) of the angular setting of the perspective 
bundle k contains a constant term a caused by systematic errors of setting the 
convergence of the verticals at the ends of the base and a variable term &x 
representing the difference in inclination of the two cases (k& — 1) and & to the 
horizon: 9x = a + ex, where the inclination of the base 
= No ji 
Sk $1 Le —(k—1)a 
> 
“ 
and the value of the vertical component bz. — (b — A bx) sk. The model n being 
supposedly supported by known vertical control points, we have 
a : 
o [suco as 29 | :(n — 1) 
3. The y-setting qx of the k projector. The systematic error f — f — f 
of the relative y-tilt setting of the two projectors changes linearly the y-tilt of 
the model, the correct setting being : 
(x = ix — (k— 1) f 
one can find f from the relation 
7 
AUT 
Z Z 
Y b dose X fheo-ipnbeal | 
a-nfsg- Man fas)-e MES Te 
or, after rocking the model » on its vertical control points, which furnishes q». 
ß = (in— Pn):(a —1) 
4. Bearing gi of the air base. y is the systematic error of relative bending, 
: ; : ; 
A x the difference of the abscissas from the same passpoint À or À having the