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The diffuse-surface optical model has been used to analyze the elastic scattering and interaction cross-section data obtained from 94 meters of positive $K$-meson track in nuclear emulsion between energies of 100 and 150 Mev. The analysis was carried out on the SWAC digital computer through the use of the existing proton code which required but slight modification, such as the use of the Klein-Gordon equation. A thorough investigation was made of the number of energy intervals and representative emulsion nuclei that were required for adequate accuracy in the computed averaged cross sections. This number was found to be one energy and two representative emulsion nuclei (heavy and light). The four parameters (${R}_{0}$, the radius parameter; $a$, the edge thickness; $V$, the real part of the potential; and $W$, the imaginary part of the potential) were varied and the goodness of fit was tested by means of the ${\ensuremath{\chi}}^{2}$ probability, there being nine degrees of freedom. An attractive real potential is fairly clearly ruled out and good fits were obtained for a repulsive real potential for a fairly wide range of physically acceptable geometrical parameters. If the ${R}_{0}$ and $a$ are chosen from electron-scattering experiments, then $V=21\ifmmode\pm\else\textpm\fi{}4$ Mev and $W=\ensuremath{-}11.0\ifmmode\pm\else\textpm\fi{}1.5$ Mev. If ${R}_{0}$ is increased to 1.20\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}13}$ cm, then $V=14\ifmmode\pm\else\textpm\fi{}2.5$ Mev and $W=\ensuremath{-}7\ifmmode\pm\else\textpm\fi{}1$ Mev.

In 50 meters of 200 to 300 Mev K/sup +/-meson track followed in nuclear emulsioii. one interaction event was found from which a pion track emerges. The incoming K/sup +/ meson had a kinetic energy of 323 plus or minus 20 Mev. The K/sup +/ meson re-emerged with an energy of 30 Mev at 36 degrees. Thc pion track has a characteristic pi - ending, and the pion was emitted with 34 Mev at 96 degrees. ln addition a 40-Mev proton left the star at 81 degrees and there are three other short tracks. Although the kinematics admit an analysis in which no inelastic secondary process occurred among the primary reaction products. strong inelastic secondary processes are quite possible and must be considered. Change independence holds important implications for the pion yield change ratios and the early trend of negative excess seems rather striking. (auth)