Olacinaceæ

Natural family of flowering plants, of the cla Angiospermæ and sub-cla Dicotyledons, comprising 61 genera and ab. 275 species, distributed through the tropical and warm regions of both hemispheres. Oil Well. Usually 5 to 8 in. in diameter, bored through the overlying strata to reach oil-bearing rock. The reports of the 2d Geological Survey of Pa. contain detailed records of several you sand wells. The producing wells in Pa. seldom ex- ceed 2,000 ft. in depth or penetrate to more than | Oscar I. 400 ft. below the sea- IMG:content-1647.png:[graphic] Oil Wells in Pennsylvania. level. The Watson well, near Titusville, non-producing, was sunk to a depth pth of 3,553 ft. To prevent the influx of water from porous strata pa ed through in sinking, the wells generally have to be cased or lined with water-tight tubing. In some wells the oil rises naturally to the surface and overflows, at least for a time; in others resort is had to pumping. The life of a well, or the length of time it will yield oil in profitable quantity, va ries with the extent and the geological character of the stratum from which the supply comes. See PETROLEUM.