George B. Mangold is a registered chemical 

 engineer and has a B.S. and an M.S. degree in 

 chemical engineering from the University of 

 Southern California. He worked for many 

 years in the research laboratories of Baroid 

 Sales on developments in drilling muds and 

 mud-testing equipment. After a brief period 

 in Venezuela as a mud engineer, he joined 

 the Petroleum Engineering Associates, Inc., 

 in Pasadena, California, where he is now 

 Laboratory Director. He has conducted re- 

 search work on drilling muds and oil-well 

 cements and has been active in core-analysis- 

 technique research and standardization studies 

 and in pursuing new methods of formation 

 logging and evaluation. 



Samuel J. Martinez received his B.S. degree 

 in chemistry from Purdue University in 1937, 

 and his M.A. degree from Tulsa University in 

 1951. He was employed as a chemist by the 

 Corn Products Refining Co. at Argo, Illinois, 

 and later served as Explosives Chemist and 

 Ballistician with the U. S. Ordnance Depart- 

 ment during World War II. He joined Dowell 

 Incorporated as Research Chemist in 1945, 

 and was promoted to the position of Technical 

 Editor in 1951. He has written and edited 

 numerous technical society papers and trade 

 journal articles, and has been responsible for 

 the preparation and issuance of operating 

 and instructional manuals within the company. 



