As the Agassiz experiment came to an end, the group realized that observations near the equator and in the southern hemisphere were needed to extend their conclusion that air shower arrival directions are nearly isotropic. Consequently, Clark, in collaboration with Vikram Sarabhai, ran his smaller experiment at Kodaikanal, India, at a latitude of 10° N, and confirmed the absence of anisotropies. Later, at the suggestion of Ismael Escobar, the Agassiz equipment was moved to El Alto at 4200 meters on the Bolivian plateau at 16° S. Here, Clark, Escobar and Juan Hersil found no anisotropies, but they showed that the structure of air showers at their maximum development is different from that at sea level.