Suggests a method treating geometric optics using a microcomputer to do the calculations of image formation. Calculations are based on the connection between the composition of lenses and the mathematics of fractional linear equations. Logic of the analysis and an example problem are included. (JM)

Describes a search and match computer program which retreives from a user-generated mineral file those minerals which are not incompatible with the observed or measured optical properties of an unknown. Careful selection of input lists make it unlikely that the program will fail when reasonably accurate observations are recorded. (Author/JN)

Highlights of this overview of virtual reality include optics; interface devices; virtual worlds; potential applications, including medicine and archaeology; problems, including costs; current research and development; future possibilities; and a listing of vendors and suppliers of virtual reality products. (Contains 11 references.) (LRW)