The monomolecular film technique for reducing evaporation from water surfaces has been applied to the problem of transpiration from plants. Hybrid corn grown in soil enriched by various amounts of fatty alcohols such as hexadecanol has required up to 40 per cent less water during its growth than control plants. It is theorized that some of the transpiration from corn plants can safely be reduced by the blocking action of molecules of hexadecanol carried through plants and deposited at the stomate water‐vapor interface. Although the blocking action could be taking place throughout the plants, testing with C14 hexadecanol has produced radioautographs showing activity not only in the roots and stalks but also throughout the leaves of treated corn plants. Comparative testing has been done in the greenhouse; however, one treated corn crop, grown naturally, yielded over 100 bushels per acre. Chemical tests on this corn showed no apparent effect of large doses of hexadecanol added to the roots of the plants.

Abstract-Techniques used for measuring the effect of monomolecular films to suppress evaporation from water surfaces are reviewed. A brief history of chemical studies and field testing of organic compounds is presented. Research in Illinois by the State Water Survey indicates that normal evaporation may be reduced by as much as one-third by efficient use of monolayers.

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A detailed study of lake evaporation in Ilhnois has been made utilizing a technique developed by the United States Weather Bureau. Monthly lake evaporation and pan evaporation have been computed for a 52-year period utilizing parameters of air temperature, dewpoint, solar radiation, and wind movement. Records of seven weather stations in and around Illinois were used. The results were checked against observed pan evaporation data for various periods of years available at seven locations. The resulting map of annual lake evaporation in Illinois is based on considerably more information than was previously available and permits more efficient design and operation ooe water supply impoundments. (

Abstract-During the summers of 1957 and 1958 studies were conducted on two lakes in central Illinois to determine a practical method of applying monomolecular layers and to learn the effectiveness of the layers in reducing evaporation. Results showed a saving of 43 per cent in 1957 and 22 per cent in 1958 of the water normally lost to evaporation. A method was developed for determining the strength of the monolayer by measuring the heat gradient near the water surface.