(1) 
f 
f 
x '=+ x >-z 
y '=+ y , 4 
X "= + (Xi — Bxj) 
Y"= + (Yi-ByO^ 
Stereocartograph V, as usually most first class plotters is preset 
for automatic recording of X i} Y i5 Z ; ; automatic recording of Bx i5 
By ; would be fairly difficult to achieve. 
By another procedure, which we prefer to the former one, the variat 
ion of Z should be left free and Z ; is recorded together with X 5 
and Yj values (by the usual means already provided for), adding 
automatic recording only of By h this being very easily done with 
Stereocartograph V as it is fitted with an appropriate exit shaft. 
In this case, values sought are obtained through the same formulae 
(see 1) with the only difference that Bx is constant whereas Z is 
variable. Of course in both cases the recorder must be in a position 
to record four coordinates. 
When using Stereocartograph V as a Stereocomparator, remark 
able advantages result not only from preventive correction of distor 
tions, but also from automatic correction of the accidental defor 
mations in photographic images ; the latter operations are performed 
by the auxiliary devices we are describing hereafter. 
Q ATTACHMENTS: CORRECTING DEVICES (see fig. 3a- 
6-7-8). 
There are four correcting devices for each camera: two (sx and sy) 
are used for correction of « systematic instrumental errors » related 
to directions X and Y, while the other two (ax and ay) are 
meant to correct chiefly accidental errors of photographic images. 
The correction of the systematic instrumental errors is performed 
by two appropriate cams which automatically impart the proper ro 
tation to optical plane 65 (also applied in high accuracy measurement 
of vertical parallaxes, as mentioned previously), whereas accidental 
errors of photographic images are corrected by means of two other 
cams which automatically produce slight shifts of the photograph 
(ph II) with respect to a « grid slide » (51 fig. 3a) on which it rests.