718 J. H. GARDNER THE MID-CONTINENT OIL FIELDS 



the Cherokee shale) are the ideal ones that, coupled with man's endeavors, 

 have brought fame to the Mid-Continent fields. 



Quality of the Petroleums 



The average crude petroleum in Kansas and Oklahoma is dark green 

 in color by reflected light, brownish by transmitted light, and has a Baume 

 gravity of about 34 degrees. Certain districts, as, for instance, Muskogee, 

 furnish oils that are yellowish green in reflected light, or bright wine 

 color in transmitted light, and run as high as 38 degrees Baume gravity. 

 A further example of superior grade petroleum is that of the Madill field, 

 Oklahoma. This has a dark olive color in reflected light, or dark wine 

 in transmitted light, and runs as high as 47.5 Baume gravity. From 

 G-arber and Ingalls are obtained green oils of 43 degrees Baume gravity. 

 As examples of petroleum of slightly inferior grades may be mentioned 

 that from the Healdton field, Oklahoma, which is a very dark oil, with 

 an average Baume gravity of about 30 degrees, and runs somewhat low 

 in its content of light distillates. Petroleums from the deeper sands, as 

 at Cushing and Blackwell, Oklahoma, or at Augusta, Kansas, average 

 between 35 and 40 degrees Baume gravity and run relatively high in 

 gasoline and other light products. Petroleums from the Petrolia and 

 Electra fields, Texas, have a dark brown color in reflected light, and 

 range from 39 to 45 degrees Baume gravity, but are not so high in many 

 of the light distillates as petroleums from Kansas and Oklahoma. Petro- 

 leum from the recently discovered Thrall field of Texas is rather light in 

 gravity, and has a brownish color somewhat similar to the better grades 

 at Corsicana and Moran, Texas, or at Caddo, Louisiana. Local areas in 

 Texas, as, for instance, the Brownwood district, furnish petroleum run- 

 ning low in gravity and high in lubricating constituents, resembling in 

 this respect oil from the Healdton field, although of lower gravity. 



While the Mid-Continent petroleums are rarely free from asphalt, this 

 constituent is in very small quantity, varying from zero to 5 per cent. 

 The accompanying table of analyses will serve to give a general compari- 

 son of the different grades. 



