Ervin George "E. G." Bailey (1880-1974) was a combustion engineer, inventor, and businessman.

Bailey was born in Damascus, Ohio, on December 25, 1880. He was mechanically precocious as a child and invented a number of mechanisms while working in his father's sawmill and farm. He studied mechanical engineering at The Ohio State University under E. A. Hitchcock (1866-1948), and was a classmate and friend of Charles F. Kettering (1876-1958), later of General Motors. After five years in the Test Department of the Consolidation Coal Company, Bailey was recruited by Arthur D. Little (1863-1935) of Boston to establish a Coal Department in 1907. Two years later, he established the Fuel Testing Company with two college friends.

In 1915, Bailey invented the Bailey boiler meter, the first device to accurately measure boiler inputs and steam output. The Bailey Meter Company was organized in Boston on January 1, 1916, and moved to Cleveland three years later. In 1922, Bailey produced the Bailey automated control system, which regulated the air and fuel supply to boilers. The Bailey meters were part of the culmination of traditional steam technology, achieving maximum efficiency from coal-fired boilers.

Bailey sold the controlling interest in the company to the Babcock & Wilcox Company in 1925. He became president of another B&W subsidiary, the Fuller-Lehigh Company, a manufacturer of coal-pulverizing equipment, and moved to Easton, Pennsylvania. He also served as a B&W vice president from 1931 to 1951 and became B&W's largest individual stockholder. In 1927, B&W sold a one-third interest in the Bailey Meter Company to General Electric in return for GE's flow-meter business. GE sold its shares back to B&W in the early 1950s. However, the purchase gave Bailey Meter access to GE's expertise and enabled it to expand into the field of electrical and electronic process controls and cultivate the chemical and nuclear industries as traditional steam technology became obsolete. B&W was absorbed by McDermott International in 1975, and the Bailey Meter Company was renamed the Bailey Controls Company. On November 1, 1989, Bailey was sold to Elsag, a subsidiary of an Itallian conglomerate.

E. G. Bailey retired as chairman of the Bailey Meter Company in 1956. He continued to be active in consulting work and engineering education until shortly before his death at Easton on December 18, 1974. Bailey held 141 patents and was the recipient of many engineering honors, including the Fritz Medal in 1952.