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As both butane and propane boil at relatively low temperatures, they exist in the gaseous state unless they are contained under pressure or are refrigerated. The boiling point of commercial butane at normal atmosphericpressure is about 30°F and that of commercial propane is about €”45°F. Both are therefore necessarily supplied under pressure in containers filled to about82€”90 per cent of their capacities. The storage pressure for liquid butane is about 25 Ib per square inch and that for liquid propane about 100