Mr. Contini briefly explains both a film about photosynthesis and a pictorial history of solar energy, including Hero's solar devices in Egypt, Frank Schuman's 1910 solar pump for irrigation, C. G. Abbott's solar flash boilers, and Felix Trombe's solar ovens for industrial uses. Dr. Telkes shows photos of a solar-heated house in Massachusetts and explains a diagram of its operation and a graph of its chemical storage method. She refers to recent books on energy sources of the future by Palmer C. Putnam and Eugene Ayres. Dr. Telkes displays the experimental solar oven she has designed for primitive civilizations in the tropics, and a film shows the oven's success in baking rolls. Solar stills are useful for desalination of salt water, according to Dr. Telkes. She refers to a large one built by Charles Wilson in Chile and demonstrates a still's use with a simple model. She notes that the U.S. Dept. of Interior's saline water program's goal is to convert arid lands through solar still irrigation.