Half-plate. [Original photographs taken] in 1902 when on drilling salt wells at depth of 1400 feet a natural gas pocket was tapped which immediately took fire and caused an explosion and a column of flame which continued for a week. When the gas pocket was first struck the pressure was 2500 lbs to the sq. inch. Enlargements of these views are in the Standard Oil Cos office at Cleveland, Ohio. The site of this explosion is right on the edge of the oil belt in Ontario, which consists of Lambton and Middlesex counties.