After Edwin Drake drilled the first commercially successful oil well in 1859, the new oil industry needed better ways to extract oil. Steam engines were first used to drill wells and then left in place to lift oil to the surface, but as production declined, running a boiler and maintaining a steam operation at each well became uneconomical when output was often only a fraction of a barrel per day. Installing gas engines or converting existing steam engines to gas removed much of the fuel and labor needed to produce oil for only a few hours. Because new gas engines were expensive, converting the steam engine already used to drill the well was usually more practical. This conversion is commonly credited to Dr. Edwin J. Fithian, a Pennsylvania physician interested in mechanics. After Oil Well Supply Company of Oil City, PA, rejected his 1897 prototype for a 10-horsepower conversion cylinder, he partnered with John Carruthers in 1898 to form the Carruthers-Fithian Clutch Company in Grove City, PA. Their converted engines, known as "half-breeds," were immediately successful, allowing an oil producer to convert a steam engine into a 10 HP gas engine for $120.00. Many companies then entered the conversion-kit market, often making two-stroke gas cylinders that could be bolted onto a steam engine bed while avoiding Carruthers-Fithian patents. By 1899, Carruthers-Fithian had become the Bessemer Gas Engine Company. Other firms also built engines designed entirely for internal combustion, and examples of both kinds still survive. The company continues today as Cooper International Corporation, a division of Schlumberger Corporation.