aerial image by electronic means has been 
developed and it is believed that it will 
eventually be possible to predict the prob- 
able resolution of a lens emulsion combina- 
tion from parameters measured for the 
lens and emulsion separately. 
REFERENCES 
1. Bennett, A. H., ‘“Aberrations of Long Focus 
Anastigmatic Photographic Objection," Sc. 
Pap. BS, 19, 587 (1922-24) S 494. 
2. Gardner, I. C., and Bennett, A. H., “The 
Compensations of Distortion in Objectives 
for Airplane Photography,” J. Opt. Soc. 
Am. and Rev. Sci. Instr., 14, 205 (1927). 
3. Gardner, I. C., “Optical Requirements for 
Airplane Mapping,” NBS Journal of Re- 
search, 8, 445 (1932) RP 427. 
4. Gardner, I. C., “The Interpretation of Lens 
Tests and Camera Calibration,” PHOTO- 
GRAMMETRIC ENGINEERING, Vol. IIT, No. 1, 
p. 13 (1937). 
5. Gardner, I. C. and Case, F. A., "Precision 
Camera for Testing Lenses," NB.S J. of Re- 
search, 18, 449 (1937) RP 984. 
6. Gardner, I. C., “The Significance of the 
Calibrated Focal Length,” PHOTOGRAM- 
METRIC ENGINEERING, Vol. 10, No. I, p. 
22 (1944). 
28 HISTORY OF PHOTOGRAMMETRY IN THE UNITED STATES 
7. Washer, F. E., “Resolving Power and Dis- 
tortion of Typical Airplane-Camera 
Lenses," NBS J. Research, 22, 729 (1939) 
RP 1216, 
8. Washer, F. E., “Characteristics of Wide- 
Angle Airplane-Camera Lenses,” NBS 
J. Research, 29, 233 (1942) RP 1498. 
9. Washer, F. E., “Region of Usable Imag- 
ery in Airplane-Camera Lenses,” NBS 
J. Research, 34, 175 (1945) RP 1636. 
10. Washer, F. E., “Locating the Principal 
Point of Precision Airplane Mapping 
Cameras," NBS J. Research, 27, 405 (1941) 
RP 1428. 
11. Washer, F. E., and Case, F. A., “Calibra- 
tion of Precision Airplane Mapping Cam- 
eras,” PHOTOGRAMMETRIC ENGINEERING, 
Vol. XVI, No. 4, p. 502 (1950); NBS J. 
Research, 45, 1 (1950) RP 2108. 
12. Norton, Mrs. C. L., “The Fairchild Preci- 
sion Camera Calibrator,” PHOTOGRAM- 
METRIC ENGINEERING, Vol. XVI, No. 5, p. 
588 (1950). 
13. Washer, F. E., and Rosberry, F. W., “New 
Resolving Power Chart,” J. Opt. Soc. Am., 
41, 597 (1951). 
14. Gardner, 1. C., and Washer, F. E., “A 
Method for Determining the Resolving 
Power of Photographic Lenses," NBS Cir- 
cular 533 (in press). 
AGRICULTURAL ADJUSTMENT ADMINISTRATION 
This bureau, an agency of the U. S. 
Department of Agriculture, inaugurated 
in 1933 the first extensive aerial mapping 
of the United States. Its Agricultural 
Conservation Program provided payments 
to farmers who curtailed planting of sur- 
plus crops through diverting acreage from 
soil depleting to soil-conserving crops and 
for soil-building practices. Aerial photo- 
graphic mapping was chosen because of its 
economy, speed, and accuracy for the de- 
lineation of the farm lands and acreage 
measurement. 
During 1934-1936 experiments and re- 
search made by W. N. Brown, O. J. 
Marshall and C. S. Coblentz demon- 
strated the feasibility of the scheme and 
by 1937 a vast mapping program was 
under way. One of the most important 
advances was the standardization of aerial 
photographic specifications. By 1948, the 
greater part of the United States, 2,500,000 
square miles, had been covered with good 
quality aerial photography available. for 
early and later use by the Administration 
and other government mapping establish- 
ments. 
The Program brought into being a large 
aerial photography industry of about 40 
operating companies, aircraft, and camera 
equipment and a nation wide organization 
of photogrammetrists and technicians. 
FOREST SERVICE 
Tracing the use of aerial photographs 
by the U. S. Forest Service reveals an 
extremely interesting chronicle in the de- 
velopment of photogrammetric techniques 
and equipment. 
Although evidence points to the fact 
that a number of Forest Service officials 
were cognizant of the inherent possibilities 
available in aerial photos, Rolph Thelen 
in 1919! seems to have been the first to put 
his thoughts on paper. Drawing on the ex- 
perience of the Air Force during World 
War I, he outlined the general scheme for 
utilizing aerial photographs for mapping 
and for resource studies. Although his 
paper brought no immediate results as far 
   
  
  
  
  
   
    
    
     
   
   
   
   
   
  
   
   
   
  
   
  
   
  
    
  
    
   
   
        
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