In Fig 3, there is a contact scale reproduc- 
tion of a stereogram of the pavement sample 
of which a formline plot is reproduced in 
Fig 4. In this stereogram the object incorpo- 
rates the gridplate replica to which refererce 
has been made, giving adequate and accurate 
planimetric control, while some height control 
is provided by arrangements of gauge blocks 
standing on that gridplate replica, the sur- 
faces of which envelop the height range of 
the pavement sample. Against each gaugeblock 
arrangement the height dimensions of each 
block comprising that arrangement were recor- 
ded in the units (inches or millimetres) in 
which they were known. 
  
Fig 3 Contact-scale reproduction of stereogram of pavement 
sample of which a formline plot is reproduced in Fig 4. 
Observation of these stereograms was performed on nega- 
tives in the WILD A.10 Autograph. The gridplate replica 
and gaugeblocks used as control data may be seen 
FORMLINE PLOT OF PART OF 
CRUSHED AGGREGATE SAMPLE 
FORMLINE INTERVAL IMM (0:5 MM. AUXILIARY ) 
SCALE IN MILLIMETRES 
0 10 30 
  
Fig 4  Reproducti 
  
  
  
  
  
  
   
SCALE IN MILLIMETRES 
  
  
  
on of a fairdrawing of a formline plot of 
the pavement sample of which the stereogram is repro- 
duced in Fig 3. The formline interval is half a 
millimetre on the faces of individual pieces of 
aggregate