472 ANNUAL, REPORT SMITHSONIAN INSTITUTION, 19 3 2 



for pilot and photographer we made test flights at altitudes up to 

 24,000 feet above the sea. In the Fairchild aerial camera, Johnson 

 installed insulating devices, grounding connections, moisture pads, 

 and a dozen or more similar gadgets until the interior of the camera 

 would hold no more. 



From those experiments we came to certain conclusions that seemed 

 to be quite definitely established. We got no static effects in photo- 

 graphs made at altitudes up to 14,000 feet provided that the expos- 

 ures were made on the way up and not on the descent. For some un- 

 known reason there was very little static in vertical photographs, 

 although the reason may be because in the vertical photography the 

 camera was mounted in the ship and not exposed to the outside air 

 as directly as when it was held by hand out of the window in the 

 making of obliques. Whether the sky was clear or overcast seemed 

 to make little difference. Rewinding the film as slowly as possible 

 helped to a slight degree. And, finally, even when the entire roll of 

 110 photographs was exposed at extreme altitudes the first 50 ex- 

 posures were generally free from static. The last two experiments 

 are to us the most significant. It seems logical to conclude from them 

 that the speed with which the film is unrolled from the spool to 

 some extent regulates the generation of static; for, as the end of 

 the roll is reached the spool turns faster and faster as the film is 

 pulled away from a core of steadily decreasing circumference. It 

 is our belief that if the film were cut to 50 exposures and rolled on a 

 thicker spool, the occurrence of static would be greatly reduced. 



All our lower shots were made on the way up not only as a result 

 of these experiments but also because we found that in coming down 

 from high altitudes the lens of the camera became so coated with 

 moisture that it was impossible to get clear exposures, as no amount 

 of wiping would clear it. 



SUMMARY 



The Shippee-Johnson Peruvian Expedition, with Lieut. George R. 

 Johnson and m^'^self as coleaders, Irving Hay as pilot, Valentine Van 

 Keuren as civil engineer, and Max Distel as mechanic, was organized 

 to carry out a number of projects of aerial photography and survey- 

 ing conceived by Johnson during his service with the Peruvian Naval 

 Air Service. 



The work of the expedition except for that done among the people 

 of the Colca Valley and based on a questionnaire prepared at the 

 American Geographical Society Avas almost exclusively photographic. 

 Our equipment was two Bellanca cabin monoplanes, one of which was 

 especially equipped for photographic work of all kinds, and a full 

 complement of aerial cameras and motion-picture machines of tlie 



