Further Results from the Study of Sea-Level Penetrating Showers

Thirty-five non-ionizing link showers (produced at a 17-g/${\mathrm{cm}}^2$ Pb plate) associated with sea-level penetrating showers are presented. These have their axes oriented toward the origins of the penetrating showers and are believed to be cascade electronic showers initiated by high energy photons, which are probably produced from the decay of ${\pi }^0$ mesons among the penetrating shower particles. The size distribution of these showers is given showing a spread from 2 to 20 particles per shower. The angular distribution of their axes with respect to the penetrating shower axes is also approximately determined.