these photographs. It is clear, that the floating mark has to be put then 
y •, 
on thia plane of reference. If we put the mark on the nadir point, then. 
the index will show on the scale of the 2-column the flight height above 
this nadir point. If the basis of the stereogram is not horizontal, 
then we have f Q . / 100 s , the flight heights of the photographs can be 
easily deduced from the Pig.1. The construction of the Wild A8 autograph 
enables only the direct reading from the 2-column - the height of the 
central point of the basis above, for example, the nadir point, on 
which the mark was put. Prom the Pig.1. we can see, that to the height 
from the Z-column of the autograph we have to add or to subtract the 
value of 
Z*H • \ . 0.0, .sin f - \ . b . sin 1 / 5 
2 12 og 2 og 
. - /3/ 
Thus the formula for the determination of height of the left or right 
photograph above the respective nadir point will be: 
. • /4/ 
The sing of the second component in this formula may determined from 
the value of reading; if9^ off y 0 /taking the null position into 
account/ then to determine the height of the right photograph we have 
to subtract the second component. 
It may be of interest what will be the extreme value of the second 
component of the formula /4/. 
If, for example b * 140 mm, it occurs when the ratio of the picture 
scale to the scale of the stereogram is 1:2 by p = 60 % and for the 
image size 18 x 18 cm and when * 0,5^ /it is rather rare/ we 
1 
shall have 
A H * j . 140 . 0,00783 * 0,55 mm 
If we put f * 115 mm, then the position of the column will be 
H kol « 230 mm and the ralative error in the determination of height