On the subject of present-day methods of location a recent contributor to “The Lamp,” an American oil journal, provides much interesting data. Oil geology, he points out, is not an exact science but it enables one to focus exact information upon the creation of a theory regarding the probable structure of an untested area. In Oklahoma, for instance, geological investigations made within the past five years resulted in the discovery of many of the new pools. All drilling is in some sense speculative, or to use the oil man’s phrase, a “wild cat,” at the outset; but in Oklahoma it was found that the proportion of dry holes on territory recommended by the geologists was less than one-third of the failures that resulted before that science was invoked. The speculative nature of the oil business in its initial stages is indicated by the fact that less than one per cent. of the area of the oil region of Pennsylvania is producing territory, although it has probably been more thoroughly drilled than any field in the world. The limited extent of even the permanently productive fields is one of the phenomena of petroleum. More than one-half of the production of the State of Wyoming is found within an area of not more than six square miles. The famous Tepetate-Casiano pool of Mexico, which produced more than seventy-five million barrels of oil from 1910 to 1918, is about one-half mile wide and three miles long. When we compare the acreage of oil areas with that of the continent, the analogy of the needle in the haystack at once suggests itself. The geologist draws the certain deduction that oil migrates through some porous formation from its original source and concentrates itself in detached “pools” of comparatively small dimensions. It is the oil pioneer’s business to find these pools. Again, there may be several successive deposits of what are known as “oil sands,” separated from each other by hundreds of feet of barren formation. The depth of a well in itself means nothing. The operator must know in what strata he expects to find the oil. If these beds prove dry, then he abandons the test, regardless of whether the drilling has reached 1,000 or 4,000 feet.