Oxygen mask

The oxygen mask didn't require genius—it required altitude. By 1917, military aircraft could climb to 20,000 feet, but human physiology couldn't follow. The invention emerged from convergence: compressed gas storage (1880s), vulcanized rubber (1839), and airframes that finally outpaced biology.

Three distinct technological lineages had to mature. First, compressed gas cylinders—developed in the 1880s initially for beverage carbonation. Early oxygen storage used glass containers, but seamless steel cylinders for high-pressure storage emerged when manufacturers could forge and test metal vessels. By 1883, liquid oxygen production became viable.

Second, vulcanized rubber transformed the material from temperature-sensitive gum into durable, flexible seals. Charles Goodyear's 1839 discovery created rubber that remained pliable in sub-freezing cockpits while maintaining airtight seals—exactly what high-altitude aviation would demand.

Third, aviation development created selection pressure. By WWI, combat altitudes exceeded 10,000 feet where hypoxia begins, and reconnaissance aircraft pushed toward 25,000 feet. The Royal Flying Corps' physiological tests proved humans needed supplemental oxygen, not better willpower.

The first solutions were brutal: German dirigible crews used mouthpieces clenched between teeth, fed from heavy iron flasks—constant-flow oxygen vented into ambient air, water vapor froze in lines.

The breakthrough required medical crossover. In 1938, Mayo Clinic physicians Walter Boothby, Randolph Lovelace, and Arthur Bulbulian developed the BLB mask for hospital oxygen therapy—then adapted it for high-altitude flight. The A-14 mask debuted in 1943, making WWII's strategic bombing viable. Without reliable oxygen delivery, B-17 crews couldn't sustain 8-10 hour missions at 25,000-30,000 feet. Medical applications followed military development.