Mechaa nkebi ahịrịokwu a: Ụlọ ahụ ka oge ya mma n'ihe gbasara nkà na ụzụ. Ụlọ ọrụ Ray Oil Burner nke San Francisco rụnyere usoro mmanụ ọkụ na-akpaghị aka, nke a na-egosighị n'ihu ọha na Bay Area ruo mgbe 1915
Panama Pacific Exposition dị na San Francisco. Tụkwasị n'ime ka ụlọ ahụ na-ekpo ọkụ, usoro ihe owuwu ahụ mere ka ndị na-ebuga akwụkwọ ozi nwee ụlọ ịsa ahụ́ na-ekpo ọkụ. Na March 9, 1910, Post Master H. L. Tripp na ndị ọrụ nzipu ozi ya kwagara n'ụlọ ọrụ nzipu ozi Santa Rosa e wuchara ọhụrụ.