"US Congress, Senate, Committee on Inter-State and Foreign Commerce, Weather Modification Research, Hearing, Washington D.C. US Govt. Printing Office, March 18-19, 1958; Lowell Ponte quotes Capt. Orville as reporting
'that the Dept. of Defense was studying ways to manipulate
the charges of earth and sky and so affect the weather I by means of 'an electronic beam to ionize or de-ionize the atmosphere over a given area' .... Capt. Orville also discussed ongoing US Air Force experiments with 'sodium vapor, ejected from jet planes to intercept solar radiation' over enemy countries and rain their weather.'
(The Cooling, op. cit. pp. 168-169.)"
http://www.fas.org/man/eprint/leitenberg/weather.pdf , page 42 (Look also to the attachment.)

PONTE, Lowell (1976). The cooling. Englewood Cliffs, N.J., Prentice-Hall. ISBN 013172312X 9780131723122 (WorldCat)
http://www.worldcat.org/oclc/2091613