GIUSEPPE INGHILLERI 
We arrange the height meter in order that the Z readings have the same unit 
as the X and Y readings (scale i : io ooo). The b z components, that in the Stereosim- 
plex III are mounted on the carriage, are gripped, so that the connection between 
the virtual intersection of the rods and the meter reading is established. 
Precision grids are mounted on the cameras, carefully levelled, through the 
rotations 9 and co. Then, for the two cameras the following operations are executed 
(see fig. 3). For the left camera, for instance, if we want to operate in the nadiral 
plane Z Y, we impose to the carriage the reading jr s and grip the X run of the 
Fig- 3 
carriage. Then, we displace the Z carriage to the position P lt the lowest possible 
(in the Stereosimplex III about 500 mm far from the taking points) to reach the best 
conditions for determination. Displacing the carriage in the Y direction, we colli 
mate the point 2 on the grid and read the Y 2 coordinate ; then, we collimate the 
point 1 and read Y x . The carriage is then moved in the Z direction to the position P 2 , 
the highest possible ; the value Z 2 — Z x (300 mm) is read on the height meter, 
the preceding operation is repeated and the values y 2 and y x are determined. 
Is evident that : 
{Y 2 — YO (Z 2 — Z t ) 
(Y.-YO-^-yO 
Zx =