Note 1 — Chapter I · PETROLEUM By John D. Northrop[1]
Reading edition
In this article, prepared in June, 1918, by Mr. Northrop, have been incorporated certain notes and additions; as, for example, information furnished by E. Russell Lloyd, of the United States Geological Survey; A. G. White and W. E. Perdue, of the Bureau of Mines, and others. (J. E. S.)