[Remark: TELEDON, a project funded by the Government of Canada, was designed to provide farmers with information related to their farming needs, such as information about weather, agricultural commodities (seeds, fertilizers, pesticides), new products, crop and animal care. A central database was used as the information repository and information was delivered to the users through telephone network and television.] LSs of girl in black, empty room at Teledon terminal, ZOOM IN to girl working at computer. CUs of girl's fingers on terminal keyboard. CU of girl's face watching terminal. CU of keyboard, hands moving into frame, using keyboard. TILT UP to screen, "PH scale" written on. Graphic sequences displayed on the screen. CU of keyboard, TILT UP to monitor and graphics. Shot of keyboard, TILT UP to monitor and title displayed "L'echelle PH". MS of map of North America, animated arrows showing wind flow, of animated map of North America, acid rates displayed on areas.