Two new methods of determining logarithmic averages of standard plate counts are proposed, the first is based on the principle that the logarithmic average of four counts is equal to the fourth root of the product of the counts: the second is a simple graphic method which also serves as a record. A similar graphic method is described for the arithmetic average of four temperatures. A nomograph for calculations of survey ratings to be used with U.S.P.H.S. Form No. 9421 is given.

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Author notes

Evan Wright was born in Garnett, Kansas. He attended Washburn College and the University of Kansas and took one of M.I.T.'s early summer courses in food technology. He was appointed a food and drug inspector for the Kansas Board of Health in 1935, and became the director of the food and drug division in 1940. For the past eight years he has been secretary-treasurer of the Association of Food and Drug Officials of the United States. His unusually developed interest in the fields of mechanics and mathematics goes back to his senior year in high school where he designed a calculator for cereal chemists which has been used in all parts of the world.