7 
construction of the bundles of rays. Of consequence for 
this decision was above all the fact that the purely 
mechanical principle in spatial arrangement offers a 
greater degree of universality than the optical-mechanical 
and the optical solutions. Because of the varied nature 
of the problems encountered in short range photogrammetry, 
adaptilility of the restitution instrument is highly 
desirable. In particular, the A40 Autograph should accept 
plates not only of the C120 camera, but also photograms 
with different focal length, taken for example with the 
.red C12 camera or with other comparable makes. It seemed 
moreover useful not to restrict the instrument to the 
normal case only, but to extend its design to allow 
also for plotting from small-phototheodolite pictures, 
t, This necessistated provisions for the orientation of 
y terrestrial photos taken with parallel-averted axes 
from base stations of different elevation. Application 
of the mechanical principle in a spatial arrangement 
permitted the realization of these wishes without 
leading to undue complexity. 
For a restitution instrument of highest possible ver 
satility, it is furthermore essential that graphic 
planimetric plotting not be restricted to the horizontal 
plane only; the alternative of plotting in the plane 
, of elevation must be possible. Also, provision should 
be made for the connection of a coordinate printer 
for the recording of rectangular spatial machine coordinates. 
a All these requirements have been considered in designing 
the new A40 Autograph, and fulfilled in its construction. 
B. Constructional features of the instrument 
The external appearance of the A40 Autograph is 
characterized by the stable horizontal base plate;, 
supported on three legs, with a bridge-like structure 
rising from its front. The base plate carries the X 
rails with the cross slide system. This is moved in two 
coordinate directions by means of handwheel-driven 
1 measuring spindles, but it can also be released from 
the spindles for rapid movements. The vertical Z column 
is rigidly mounted to the upper carriage of the cross 
er slide system; the column carries the Z carriage with the 
base component movements. When plan views are being 
plotted, the Z carriage is moved by means of the foot 
disk. The plotting table is positioned to the right of 
the instrument; through a gearbox with interchangeable 
gear wheels, the movements of those spindles or propulsion 
rods presently coupled to the handwheels are transmitted 
at the corresponding ratio. With the turn of a knob, the 
functions of the right handwheel and of the foot disk 
can be interchanged. This means that the plane of the 
drawing can be selected to represent either the hori 
zontal (XY) plane or the plane of elevation (XZ) of the 
Autograph. The foot disk drive is connected through