It also chanced that this whole country abounded in signs of petroleum.
This petroleum also contains asphalt and other chemical products.
It has a grade of petroleum that differs from any other thus far found in the world.
Kerosene oil is only one of the many substances found in petroleum.
The petroleum is conveyed by pipe lines to the refineries at Baku.
Petroleum is a mixture of various compounds known as hydrocarbons.
Nickel, petroleum, silver, and lead form the rest of the output.
A story of the petroleum days, and of a family who struck oil.
There are numerous beds of coal, and also petroleum springs.
Between 1857 and 1918 the world's production of petroleum was 1,005 millions of tons.