CHEMICAL ABSTRACTS SERVICE (CAS), IN CONJUNCTION WITH THE NATIONAL SCIENCE FOUNDATION, CONDUCTED THE FIRST PUBLIC DEMONSTRATION OF CAS COMPUTER-BASED SUBSTRUCTURE SEARCH TECHNIQUES AT THE 152ND MEETING OF THE AMERICAN CHEMICAL SOCIETY IN NEW YORK CITY. FROM SEPTEMBER 11 THROUGH SEPTEMBER 16, 1966, INTERESTED PERSONS WERE GIVEN THE OPPORTUNITY TO SEE SUBSTRUCTURE SEARCH OPERATIONS AND TO DETERMINE THE TECHNIQUES, CAPABILITIES, AND POTENTIALITIES IN LIGHT OF THEIR OWN NEEDS. THE PURPOSE OF SUBSTRUCTURE SEARCHING IS TO ENABLE TECHNICAL PERSONNEL TO AUTOMATICALLY SEARCH FOR CHEMICAL STRUCTURES AND SUBSTRUCTURES THAT HAVE BEEN REPORTED IN THE LITERATURE AND REGISTERED IN THE CAS CHEMICAL COMPOUND REGISTRY SYSTEM. THE NEW YORK CITY DEMONSTRATION USED A "BREADBOARD MODEL" OF THE SUBSTRUCTURE SEARCH SYSTEM. THIS IS A VERSION CAPABLE OF PRODUCING ALL OF THE CORRECT ANSWERS TO THE QUESTIONS, BUT A MODEL WITHOUT THE REFINEMENTS THAT WILL BE AVAILABLE IN AN OPERATIONAL SYSTEM. BECAUSE OF THE DIALOGUE BETWEEN CAS SCIENTISTS AND PRACTICING CHEMISTS AND CHEMICAL ENGINEERS, CAS IS NOW ABLE TO MAKE SIGNIFICANT TECHNICAL IMPROVEMENTS TO BETTER SERVE THE INFORMATIONAL NEEDS OF THE CHEMICAL COMMUNITY. THIS REPORT DESCRIBES THE DEMONSTRATION, THE BREADBOARD MODEL, AND THE RESULTS OF THE DEMONSTRATION, AS WELL AS THE IMPROVEMENTS SUGGESTED AS A RESULT OF THE EXPERIMENT. (DS)