Until a comparatively recent period the California fields held the record for production, but in 1918 the young State of Oklahoma forged to the front, with a production of more than 100,000,000 barrels in one year, and a large undeveloped territory which there is every reason to believe will prove rich in petroleum. Tulsa is the centre of the Oklahoma industry and is an example of a town which has grown suddenly from a small agricultural settlement to a thriving centre of metropolitan aspect as a result of the oil industry. There are those who believe that Texas will very shortly attain eminence equal to that of both California and Oklahoma as a petroleum region. The gulf fields came into prominence about the dawn of the present century, and have perhaps witnessed more booms than other sections of this continent. Speculative eras in new fields which have been brought in by “wildcat” drilling, which term should not be confused with wildcat mining speculation, are however regarded by sane and conservative oil men as harmful rather than helpful to the petroleum industry. They invariably produce false inflation and subsequent depression; and involve in reproach one of the greatest economic blessings bestowed upon humanity. Thus far we have surveyed petroleum in its many general aspects and the remainder of this treatise will be devoted to a description of its production, subsequent treatment and manifold application to the needs of present day commerce and civilization. CHAPTER VI LOCATING THE OIL WELL When Edwin Laurencine Drake went to Titusville, in 1859 the first question he asked of the natives was the location of “the oil spring” known to the Indians and the farmers who succeeded them. The modern oil seeker no longer concerns himself with surface indications. In truth there is little or nothing in the contour of the latter-day oil-fields to suggest oil to the eyes of the uninitiated. But geologists first located probable oil bearing formations and have made calculations of the formations two or three thousand feet below and the drilling sites are located in accordance with them. Roughly, the theory upon which such operations are based is that the sub-surface rocks undulate, and that the presence of oil is most assured at the highest points of the undulations. By measuring dips at given points they calculate the distance in a certain direction to what they deem the most favourable site and surveyors proceed to fix and designate it. In cases, not infrequent when the lease which conveys the right of drilling is limited in area, it is the business of the surveyor to see that the site chosen is well within the boundaries of the plot acquired for drilling purposes.