RAREFIED AIR

Hokitika Guardian, 30 December 1932, Page 7

RAREFIED AIR

TESTS WITH ANIMALS. SAFETY LIMITS OF FLIGHT. LONDON, December 10. That only poets can soar safely into the empyrean is the conclusion of Sii Leonard Hill, late director of applied physiology at the National Institute of Medical Research at Hampstead, as the result of experiments in which he watched the effects of withdrawing the oxygon from a steel chamber containing animals. A monkey slept when the density of the oxygen became one-sixth of that in the air at the earth’s suriace, a goat began to die with the density at oneseventh, mice and other small animals were tougher, while birds withstood rarefication to one-ninth of the normal air density. Drowsiness gave the first warning or danger and convulsions due to the stoppage of lung action followed, whereupon the oxygen was restored and the anima's recovered. Sir Leonard Hill declared that the symptoms correspond with those experienced by climbers and airmen at high altitudes. The safety limits of flight, lie said, appeared to be 20,000 ft. for airmen and breathing t/he surrounding air and 50,000 ft. for airmen breathing supplies of oxygen.