436 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1954 



time were superior to those of British fighters. Thanks to the efforts 

 of the Flying Personnel Research Committee and particularly to one 

 of its members, Sir Brian Matthews, the British developed a success- 

 ful oxygen mask and a system of supply that made it possible for 

 British fighters to meet German raiders at their own altitude, and 

 through this circumstance the Battle of Britain was won, virtually in a 

 single day, September 15, 1940, when 186 German planes were shot 

 down. The Luftwaffe quickly decided it could no longer stand this 

 rate of attrition. The British were tireless in their efforts to improve 

 their oxygen masks and modes of supply, and our own air forces prof- 

 ited immeasurably by British experience, which was made freely 

 available to the U. S. Army and Navy Air Forces. 



Pressure-cabin aircraftP — It early became obvious to some investi- 

 gators, including Paul Bert, that, if the gondola of a high-altitude 

 balloon were artificially pressurized, a balloon might ascend higher 

 into the atmosphere without endangering life. But years passed, and 

 it was not until 1933 that the National Geographic-United States 

 Army stratosphere flight was able to make an ascent in a pressurized 

 gondola with adequate pressure control. In this memorable ascent, 

 Auguste Piccard achieved an altitude of 72,395 feet, the highest alti- 

 tude yet attained by man. 



The experience encouraged the United States Army Air Corps to 

 think of pressurized combat aircraft, and to Harry G. Armstrong, 

 now Surgeon General of the United States Army Air Forces, must 

 be given credit for having, through a historic Air Corps teclinical 

 report, outlined the physiological requirements of sealed high-altitude 

 aircraft compartments. This was a starting point for developments 

 of pressurized planes in this country, the first of which (the XC-35) 

 was flown in April 1937. In this development the United States was 

 ahead of both Britain and Germany and, thanks to the enterprise of 

 the Lockheed Aircraft Corp., finally succeeded in making their strato- 

 liners (B-307) and Constellations effectively pressurized. After 1946 

 Constellations began to make regular transatlantic flights at altitudes 

 ranging from 18,000 to 24,000 feet, while the pressure in the cabins 

 was maintained at an average corresponding to 8,000 feet. 



Technical difficulties in pressiire-cabin aircraft prove numerous, 

 and for the most part they stem from man's physiological requirements, 

 i. e., maintaining cabin pressure, and, of almost equal importance, ade- 

 quate ventilation. The average air passenger, without lung or heart 



"The material in this and the following section is based on Fulton, J. F., 

 Aviation medicine in its preventive aspects: An historical survey (Heath Clark 

 Lectures, 1947), London, 1948. National Research Council, Decompression sick- 

 ness, caisson sickness, diver's and flier's bends, and related syndromes, Phila- 

 delphia, 1951. 



