oil dero set

[ME., In every pounde of oil an unce of rose Ypurged putte, and hange it dayes seven In sonne and moone, and after oilderose We may baptize and name it. Palladius , Husbondrie (E. E. T. S.), p. 156. oil-derrick (oil'der"ik), n. An apparatus used in well-boring for mineral oils. It is a strong wooden frame, from 16 to 20 feet square at the base, which is formed of heavy sills of oak or other suitable timber, and it tapers toward the top, which is from 60 to 75 feet above the sills. The corner parts are made of heavy pine planks, usually about 2 inches thick and 10 inches wide, spiked together at right angles, and bound to each other by cro -pieces and diagonal braces. A ladder is constructed on one side, extending from the bottom to a heavy cast-iron derrick-pulley supported in the upper part of the frame. The oil-derrick and its acce ories are used IMG:content-1668.png:[merged small][merged small][merged small][merged small][ocr errors][merged small][merged small][merged small][merged small][merged small][merged small][merged small] bar to operate the various tools employed in well-boring, such as the temper-screw, rope-socket, auger-stem, sinker-bar and substitute, jars, bitts, flat reamers, etc. A similar derrick is used for sinking deep wells where water only is sought. See well - boring.