Two or four large wind machines running together provided a greater temperature response per machine than one alone in citrus frost protection tests made in Riverside during the 1952-53 winter. The responses depended on the spacing of the machines.

C. E. Barbee, Associate Specialist, and H. B. Schultz, Assistant Specialist, Department of Agricultuyal Engineering, co-operated in the field work of this study.

The above progress report is based on Research Project No. 400-U and on the 1952 report by D. E. Angus, Commonwealth Scientific and Industrial Research Organization, Melbourne, Australia.

The Therm Retain Wind Machine tested in the studies reported here, was generously loaned by the manufacturer.