States and foreign countries. It is now on 
exhibit at the National Air Museum of the 
Smithsonian Institution in Washington, 
D.C: 
During World War II the Abrams 
School of Aerial Surveying and Photo 
Interpretation was formed for the training 
BAUSCH 
The Bausch & Lomb Optical Co. has 
pioneered in the development of and pro- 
duction of a great many products in the 
field of optics and scientific optical instru- 
ments in the course of its 100 years exist- 
ence. It is natural, therefore, that this 
company should have continued the de- 
velopment and improvement of the Multi- 
plex system of Aerial Mapping Equipment 
in this country soon after its inception in 
Europe. 
The first Multiplex equipment manu- 
factured by Bausch & Lomb Optical Co., 
about 1936, was designed for use with 
aerial photography taken with the Altimar 
lens of 81 inch focal length and a total 
field coverage of 68?. A relatively small 
quantity of this normal-angle equipment 
was produced for military use, but was 
very soon replaced by wide-angle equip- 
ment which was designed to accommodate 
photography with the newly developed 
Bausch & Lomb Metrogon lens, with a 
field coverage of a little more than 90°. 
This wider angle offered the advantages 
of a more favorable base-height ratio 
which increased the accuracy of the sys- 
tem, and greater economy of operation by 
reducing the number of models, and 
reducing the number of control and pass 
points. The Multiplex equipment was used 
very extensively by the military agencies 
and the U. S. Geological Survey, but it was 
not until 1946 that it was possible to make 
it available to commercial mapping com- 
panies and to foreign government agencies. 
It is now being employed by a number of 
private companies as well as government 
agencies in this and other countries. 
Another important photogrammetric 
instrument developed by Bausch & Lomb 
Optical Co. is the Autofocus Rectifier, 
completed in 1948. It is used in the recti- 
fication of aerial photographs for the pro- 
duction of controlled mosaics, and accom- 
modates camera tilts up to 20° with mag- 
  
34 HISTORY OF PHOTOGRAMMETRY IN THE UNITED STATES 
of military personnel in photogrammetry 
for the United States Marine Corps at 
Lansing, Michigan. 
Talbert Abrams served as Vice President 
of the American Society of Photogram- 
metry in 1950 and President of the Society 
in 1951. 
AND LOMB 
nifications varying from (.6) to (3.5). 
An improved model offering greater 
stability and other mechanical advantages 
has just been completed and will be in 
production in 1953. 
Improvement in photographic lenses 
and the continued increase in flight alti- 
tudes, as well as the highway construction, 
city planning, and cadastral surveys has 
produced the need for a plotting instru- 
ment of longer projection distance than 
the Multiplex equipment affords. À plot- 
ter, which employs the same basic pro- 
jection principle as the Multiplex, having 
a projection distance of 720 m/m, and 
employing 9 X9 diapositives produced by 
contact printing, has been recently de- 
signed for the U. S. Corps of Engineers. 
This instrument is a modification of the 
Kelsh Plotter designed by Harry Kelsh 
which has already proved its usefulness in 
photogrammetric programs. 
The development of photogrammetric 
instruments in the U. S. is still in its 
infancy. In looking to the future Bausch & 
Lomb Optical Co. is maintaining a photo- 
grammetric section employing a staff of 
engineers who are constantly striving to 
improve the present equipment and to 
develop new instruments to meet the de- 
mands of mapping agencies as new re- 
quirements arise. 
Research at various levels is being 
carried on by photogrammetrists through- 
out the country. New theories and new 
designs are constantly being presented. 
No instrument manufacturer can possibly 
follow every lead, nor can it design and 
produce an instrument on its own initiative 
that will be universal in satisfying the 
needs of all requirements of all mapping 
agencies. In so far as it is possible it is the 
the policy of the Bausch & Lomb Optical 
Co. to keep abreast and ahead of photo- 
grammetric development and to do its 
part in the future as it has in the past in 
    
   
  
  
  
   
  
  
   
  
  
  
  
  
   
  
   
  
  
  
  
   
  
  
  
  
  
  
  
   
  
  
  
  
  
  
  
  
  
  
  
  
   
  
  
  
  
   
   
  
  
  
  
   
  
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