1966 Press Photo Workman checks pressure tubes filled with acetate membranes.

Workman at left checks pressure tubes filled with cellulose acetate membranes which permit fresh water to flow through but hold back salt and other dissolved solids. A closeup of the cellulose acetate semipermeable membrane, which is only 5/1000s of an inch thick, is at the right. The membrane may be the answer to large desalting operations.

Photo is dated 1966.

Photo measures 10 x 8.25 inches.